hazard identification and vulnerability analysis - Mason County

MASON COUNTY
HAZARD
IDENTIFICATION
AND
VULNERABILITY
ANALYSIS
January 2009

HAZARD IDENTIFICATION AND VULNERABILITY ANALYSIS
MASON COUNTY
INTRODUCTION
“Disaster” (diz-as’-ter) n. an adverse happening; sudden misfortune; catastrophe”.
The Hazard Vulnerability Analysis is an element of hazard mitigation allowing
emergency managers to set goals according to the public need for protection.
This document enhances public and private agency understanding and
awareness, influencing the adoption of hazard mitigation programs. The findings
revealed in the Hazard Vulnerability Analysis also serve as a basis for
preparedness as well as influencing effective response and recovery programs.
The most serious events are the least likely to happen, but this also means that
data about their causes and effects are often scarce or unreliable.
This analysis covers hazards most threatening to Mason County as determined
by history, geologic projections and social and technological trends.
BACKGROUND
Mason County has a long history of emergencies and disasters both manmade
and natural that range from hazardous chemical spills to earthquakes to
windstorms. Some of the potential disasters that could affect the County, like a
major earthquake, have not happened for hundreds of years, yet the result could
be catastrophic loss of life, disruption of the County's infrastructure and long term
economic devastation. Mason County has been included in several Presidential
disaster declarations. While storms and floods make up the bulk of these, there
are others, including earthquakes, the volcanic eruption of Mt. St. Helens, and
the 1994 fishing disaster attributed to El Nino effects. In addition to these there
are many smaller emergencies, which can and have caused major disruption in
the past.
GEOGRAPHIC CHARACTERISTICS
Location
Mason County is located in Western Washington on the southeastern portion of
the Olympic Peninsula. Shelton, the County seat, is 25 air miles southwest of
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Seattle, 20 miles northwest of Olympia and 65 miles from the Pacific Ocean
beaches.
Topography
The total area of Mason County is 1,051 square miles, with 961 square miles of
land and 90 square miles of water. The salt water area includes portions of Puget
Sound and Hood Canal. The Skokomish, the Hamma Hamma, Tahuya and the
East Fork of the Satsop River are the major rivers in the County.
Two hundred thirty beautiful lakes dot Mason County. The most popular are Lake
Cushman, Mason Lake, Spencer Lake, Lake Limerick, and Lake Isabella.
Earthen dams are commonplace in Mason County. The Lake Cushman
hydroelectric project has two large, concrete dams supporting the Tacoma Public
Utilities power plants near Hoodsport.
Elevations range from sea level to 6,000 feet in the majestic Olympic Mountains.
Much of the native vegetation consists of conifers and evergreen understory. Soil
conditions include wetlands, the fertile delta-like farmlands of the Skokomish
Valley, rocky mountainous terrains, and poor soils with varying sand, gravel,
loam and clay conditions.
CLIMATE
Period of Record : 6/ 2/1948 to 11/8/2002
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Average Max.
Temperature (F)
44.5 49.1 53.4 59.5 66.9 71.8 77.1 76.9 71.9 60.9 50.7 45.0 60.6
Average Min.
Temperature (F)
33.1 34.5 35.7 38.9 44.2 49.2 52.3 52.6 48.1 42.1 37.6 34.4 41.9
Average Total
Precipitation (in.)
10.47 8.41 6.93 4.37 2.26 1.67 0.94 1.29 2.50 5.84 10.43 11.09 66.19
Average Total Snow
Fall (in.)
3.9 0.7 0.6 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.8 2.1 8.2
Average Snow
Depth (in.)
0 0 0 0 0 0 0 0 0 0 0 0 0
Max. Temp.: 98.5% Min. Temp.: 98.4% Precipitation: 98.3% Snowfall: 96.6% Snow Depth: 94.9%
DEMOGRAPHIC CHARACTERISTICS
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Population Trends
Between 2000 and 2005 Mason County’s population grew from 49,405 to 51,900,
Projections suggest a continuation of this trend, In fact, between 2005 and 2030,
Mason County’s population is projected to increase from approximately 51,900
to an estimated 80,043. Much of that growth is expected to result from inmigration
to the County rather than from natural increases.
Land use
There are several types of development patterns within the County: urban, rural
areas, agricultural, aquaculture, State and Federal Parks. Each type is unique
and separate, offering its own composition of land uses, and land use intensities
and densities. One of the most common reasons people enjoy living in Mason
County is the ability to travel from distinctively urban to an equally distinct rural
settings within a matter of minutes.
The following table presents the projections in area growth between 2005 - 2025
Area Growth Projections for Mason County
Area Share of Growth
Shelton Urban Growth Area 33%
Belfair Urban Growth Area 18%
Allyn Urban Growth Area 7%
Fully Contained Community Reserve 3%
Rural Activity Centers – Limited Areas of More Intensive
Rural Development
1.5%
Rural Lands 37%
HAZARDS
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Mason County, due to its location and geological features, is vulnerable to the
damaging effects of major natural and technological hazards. Events may occur
at any time and may create varying degrees of damage and economic hardship
to individuals, businesses and the governments in Mason County.
Potential and actual hazards are presented in the attached sections. The
sections are divided into Natural Hazards and Technological Hazards. The
hazards are listed alphabetically under each division, therefore, no inference
should be made as to severity or probability of occurrence.
NATURAL HAZARDS
DROUGHT
Definition
A drought is defined as "a period of abnormally dry weather, sufficiently
prolonged for the lack of water to cause a serious hydrologic imbalance (i.e., crop
damage, water supply shortage, etc.) in the affected area."
Extremely dry conditions could force the closure of forests to recreation, hunting,
camping and hiking, Camp fires and outdoor burning are often limited for a
couple of months each summer and longer during extremely dry conditions.
Mitigation efforts should include public information on water conservation, which
would discourage unnecessary water waste. The mitigation activities listed under
Fires - Forest, Wildland, Urban Interface, in a later section of this document, also
apply due to the increased potential for forest fires during a drought.
Large areas supplied by one water system might have to resort to rationing.
Residents on private wells should be prepared with water barrels in the event
their wells become temporarily dry.
History
Drought has not commonly been considered a problem in the area west of the
Cascade Mountain Range. In spite of this, Mason County has felt the effects of
drought many times in the past and will continue to do so in the future. Multiple
measurable and documented droughts have hit the region in the past 100 years
but the following three are the most notable:
• April 1934 – March 1937: The longest drought in the region’s history- the
driest periods were April-August, 1934; September-December 1935; and
July-January 1936-1937.
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• October 1976 – September 1977: The worst drought on record. Stream
flows averaged between 30% and 70% of normal. Temperatures were
higher than normal, which resulted in algae growth and fish kills.
• January – March 2001: the second driest winter on record in 106 years.
Stream flows approached the low levels of the 1976-77 drought.
• 2002-2003: Two of the driest summers on record. One of five driest
winters in past 100 years. Fishing was halted on rivers on the Olympic
Peninsula.
The possibility of a prolonged drought exists in Mason County. Normally, average
annual rainfall is about 64 inches, however, it may be 146 inches or more in the
higher elevations of the County. Several consecutive, hot, dry summer months
can create parched and tinder-dry conditions.
Hazard Identification and Vulnerability Assessment
Mason County’s population and business continue to grow, so does the demand
for water. As usage approaches the limit of available water, any decrease in the
normal flow will tend to exacerbate past problems. The county does not need a
full-blown drought to experience a water shortage.
Mason County is vulnerable to drought in the logging and wood products
industries as well as the recreational areas. Loss of income from hunters,
campers and tourists could have a serious effect on Mason County economics.
Besides the forests, local agriculture can be devastated by a prolonged drought.
A shortage of water will also impact certain industries that depend on
inexpensive water supplies, such as laundries and restaurants. In the event of
severe drought, the fire fighting capabilities of fire agencies can be impacted
.
Conclusions
Droughts will continue to occur in Mason County. Drought-related forest and
other wildfire will continue to occur in the County. During periods of drought,
County and City governments must perform public education concerning water
conservation and, when needed, institute water conservation activities such as
prohibition of lawn watering and car washing.
Better forest fire protection techniques have been developed and total acreage
burned continues to decrease. The increasing population and new industries will
continue to tap resources and make the area susceptible to drought conditions.
Continued good management practices of Mason County water resources will
help alleviate adverse impacts of future droughts.
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Resources
United States Geological Survey
University of Washington Geophysics Program
Washington State Department of Natural Resources
Washington State Department of Transportation
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EARTHQUAKES
DEFINITION
An earthquake is a shaking of the earth’s crust, which can be mild or violent
depending on the intensity of the quake. Some areas of the United States are
more susceptible to earthquakes than other areas. An earthquake can be felt in
an area ranging from several hundred square miles to several thousand square
miles. If damage occurs, it may be limited to dishes falling from shelves and
breaking or it may topple major buildings, overpasses, bridges and other vital
structures. The Richter Scale is used to measure the magnitude of an
earthquake. The Modified Mercalli Intensity Scale is used to describe earthquake
effects.
RICHTER AND MODIFIED MERCALLI INTENSITY SCALES
Richter Scale
M=1 to 3: Recorded on local seismographs, but generally not felt.
M=3 to 4: Often felt, no damage.
M=5: Felt widely, slight damage near epicenter.
M=6: Damage to poorly constructed building and other structures within
ten kilometers.
M=7: “Major” earthquake, causes serious damage up to one hundred
kilometers.
M=8: “Great” earthquake, great destruction, loss of life over several
hundred kilometers
M=9: Rare great earthquake, major damage over a large region over one
thousand kilometers.
Modified Mercalli Scale
I. Not felt except by a very few under especially favorable circumstances.
II. Felt only by a few persons at rest, especially on upper floors of
buildings. Delicately suspended objects may swing.
III. Felt quite noticeably indoors, especially on upper floors of buildings,
but many people don not recognize it as an earthquake. Standing
motor cars may rock slightly. Vibration like passing of truck.
IV. During the day felt indoors by many, outdoors by few. At night some
awakened. Dishes, windows, doors disturbed; walls made cracking
sound. Sensations like heavy truck striking building. Standing motor
cars rocked noticeably.
V. Felt by nearly everyone; many awakened. Some dishes, windows, etc.,
broken; a few instances of cracked plaster; unstable objects
overturned. Disturbance of trees, poles and other tall objects
sometimes noticed. Pendulum clocks may stop.
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HISTORY
VI. Felt by all; many frightened and run outdoors. Some heavy furniture
moved; a few instances of fallen plaster or damaged chimneys.
Damage slight.
VII. Everybody runs outdoors. Damage negligible in buildings of good
design and construction; slight to moderate in well-built ordinary
structures; considerable in poorly build or badly designed structures;
some chimneys broken. Noticed by persons driving motor cars.
VIII. Damage slight in specially designed structures; considerable in
ordinary substantial buildings with partial collapse; great in poorly built
structures. Panel walls thrown out of frame structures. Fall of
chimneys, factory stacks, columns, monuments, walls. Heavy furniture
overturned. Sand and mud ejected in small amounts. Changes in well
water. Disturbed persons driving motor cars.
IX. Damage considerable in specially designed structures; well designed
frame structures thrown out of plumb; great in substantial buildings,
with partial collapse. Building shifted off foundations. Ground cracked
conspicuously. Underground pipes broken.
X. Some well-built wooden structures destroyed; most masonry and frame
structures destroyed with foundations; ground badly cracked. Rails
bent. Landslides considerable from river banks and steep slopes.
Shifted sand and mud. Water splashed (slopped) over banks.
XI. Few, if any masonry, structures remain standing. Bridges destroyed.
Broad fissures in ground. Underground pipe lines completely out of
service. Earth slumps and land slips in soft ground. Rails bent greatly.
XII. DAMAGE TOTAL. Waves seen on ground surfaces. Lines of sight and
level distorted. Objects thrown upward into the air.
The Puget Sound region is entirely within Seismic Risk Zone 3, requiring that
buildings be designed to withstand major earthquakes measuring 7.5 in
magnitude. It is anticipated, however, that earthquakes caused from seductions
plate stress can reach a magnitude greater than 8.0.
The part of Washington State east of the Cascades has historically been subject
to shallow, though infrequent, smaller earthquakes up to magnitude of
6.0..Washington State is vulnerable to the following earthquake risks:
Date
Washington State Significant Earthquakes
Time
(PST)
Latitude/
Longitude Depth (Km) Mag Location
December 12, 1880 2040 47 . 30' 122 . 30' 5.5 Puget Sound
April 30, 1882 2248 47 . 00' 123 . 00' deep 6.0 Olympia area
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Washington State Significant Earthquakes
November 29, 1891 1521 48 . 00' 123 . 30' 5.0 Puget Sound
March 6, 1893 1703 45 . 54' 119 . 24' shallow 4.9 SE Washington
January 3, 1896 2215 48 . 30' 122 . 48' 5.7 Puget Sound
March 16, 1904 2020 47 . 48' 123 . 00' 5.3 Olympics eastside
January 11, 1909 1549 48 . 42' 122 . 48' deep 6.0 Puget Sound
August 18, 1915 0605 48 . 30' 121 . 24' 5.6 North Cascades
January 23, 1920 2309 48 . 36' 123 . 00' 5.5 Puget Sound
July 17, 1932 2201 47 . 45' 121 . 50' shallow 5.2 Central Cascades
July 15, 1936 2308 46.00’ 118.18' shallow 5.7 SE Washington
November 12, 1939 2346 47.24' 122.36' deep 5.7 Puget Sound
April 29, 1945 1216 47.24' 121.42' 5.5 Central Cascades
February 14, 1946 1914 47.18' 122.54' 40 6.3 Puget Sound
April 13, 1949 1155 47.06'1 22.42' 54 7.1 Puget Sound
August 5, 1959 1944 47.48' 120.00' 35 NW Cascades
April 29, 1965 0728 47.24' 122.24’ 63 6.5 Puget Sound
February 13, 1981 2209 46.21' 122.14' 7 5.5 South Cascades
April 13, 1990 2133 48.51' 122.36' 5 5.0 Deming
January 28, 1995 1911 47.23' 122.21' 16 5.0 17.6 km NNE of
Tacoma
May 2, 1996 2104 47.46' 121.57' 7 5.3 10.2 km ENE of Duvall
June 23, 1997 1113 47.36' 122.34' 7.4 4.9 5.5 km NE of
Bremerton
July 2, 1999 1743 47.05' 123.28' 41 5.1 8.2 km N of Satsop
February 28, 2001 1054 47. 09’ 122.52’. 52.4 6.8 17.6 km NE of Olympia
HAZARD IDENTIFICATION AND VULNERABILITY ASSESSMENT
In Western Washington, the primary tectonic plates of interest are the Juan de
Fuca and North American plates. The Juan de Fuca plate moves northeastward
with respect to the North American plate at a rate of about 4 cm per year. The
boundary where these two plates converge, the Cascadia Subduction Zone, lies
approximately 50 miles offshore and extends from the middle of Vancouver
Island in British Columbia to northern California. As it collides with North
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America, the Juan de Fuca plate slides (or subducts) beneath the continent and
sinks into the earth’s mantle. Mason County is vulnerable to the results of this
continual movement of the earth’s tectonic plates.
Washington ranks second in the nation after California among states vulnerable
to earthquake damage according to a Federal Emergency Management Agency
study. The study predicts Washington is vulnerable to an average annual loss of
$228 million.
A shock, which reached a maximum intensity of VII at a number of places in the
Puget Sound area was felt over about 182,000 square km, occurred on February
14, 1946. A few deaths were attributed indirectly to the shock; damage was
estimated at $250,000, mostly in Seattle. Most of the reported damage was
limited to cracked plaster and slight chimney failure, but there were a few cases
of spectacular building damage in Seattle. The magnitude 5 3/4 tremor was also
felt in southwestern British Columbia and northwestern Oregon.
One of the strongest earthquakes on record for the Puget Sound area followed a
few months later. A magnitude 7.3 shock in the Strait of Georgia on June 23,
1946, caused the bottom of Deep Bay to sink between 2.7 and 25.6 meters.
These measurements were reported by the Canadian Hydrographic Department.
Also, a 3 meter ground shift occurred on Read Island. One person was drowned
when a small boat was overturned by waves created by a nearby landslide.
Waves were reported sweeping in from the sea, flooding fields and highways.
Heavy damage occurred in the epicentral region. South of the Washington State
boundary, some chimneys fell at Eastsound and on Orcas Island and a concrete
mill was damaged at Port Angeles. Some damage occurred on upper floors of tall
buildings in Seattle. The shock was strongly felt at Bellingham, Olympia,
Raymond, and Tacoma. The total affected area in Canada and the United States
was about 260,000 square km.
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Property damage estimated at upwards of $25 million resulted from a magnitude
7.0 earthquake near Olympia on April 13, 1949. Eight deaths were caused either
directly or indirectly, and many were injured. At Olympia, nearly all large buildings
were damaged, and water and gas mains were broken. Heavy property damage
was caused by falling parapet walls, toppled chimneys, and cracked walls (MM
VIII). Electric and telegraphic services were interrupted. Railroad service into
Olympia was suspended for several days; railroad bridges south of Tacoma were
thrown out of line, delaying traffic for several hours. A large portion of a sandy
spit jutting into Puget Sound north of Olympia disappeared during the
earthquake. Near Tacoma, a tremendous rockslide involving an 0.8 km section of
a 90 meter cliff toppled into Puget Sound. The felt area extended eastward to
western Montana and southward to Cape Blanco, Oregon, covering about
400,000 square km in the United States. A large portion of western Canada also
experienced the shock.
On November 5, 1962, a moderately strong earthquake caused minor damage in
the Vancouver, Washington - Portland, Oregon, area. Numerous chimneys were
cracked or shaken down (MM VII) in Portland. Several buildings had tile ceilings
fall, and other damage such as cracked plaster and broken windows were
reported. Slight damage was reported from several towns in Washington. The
tremor was felt over an area of approximately 52,000 square km of Washington
and Oregon. The magnitude was measured at 4 3/4.
A magnitude 6.5 shock on April 29, 1965, which was centered very close to the
epicenter of the 1949 earthquake, caused about $12.5 million damage. Three
persons were killed by falling debris, and the deaths of four elderly women from
heart failure were attributed to the earthquake. There were numerous injuries, but
most were minor. The shock was characterized by a relatively large intensity VII
area and small pockets of intensity VIII damage in Seattle and Issaquah.
Extensive damage to chimneys was noted in West Seattle. In 188 city blocks, it
was found that 1712 of 5005 chimneys were damaged. Two schools in West
Seattle and two brick school buildings in Issaquah were damaged considerably.
In general, damage patterns repeated those experienced during the 1949 shock.
Buildings that apparently had been damaged in 1949 often sustained additional
damage in 1965. The tremor was felt over 340,000 square km of Washington,
Oregon, northern Idaho, northwestern Montana, and part of British Columbia.
A magnitude 5.3 earthquake hit Seattle on May 2, 1996. Information about this
earthquake is available from the Pacific Northwest Seismograph Network. o
Another earthquake struck Western Washington on July 2, 1999. Information
about this earthquake is available from EQE, a consulting company. * The most
recent major earthquake, the Nisqually quake, was a magnitude 6.8 quake and
struck near Olympia, WA on February 28, 2001.
People, buildings, emergency services, hospitals, transportation, dams, and
electric, natural gas, water and sewer utilities are susceptible to an earthquake.
Effects of a major earthquake in the Puget Sound basin are catastrophic,
providing the worst-case disaster short of war. Thousands of people could be
killed and many tens of thousands injured or left homeless. An earthquake in the
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Puget Sound basin would directly affect Mason County either through mutual aid
needs or through refugee migration into the county. Earthquake activity in
eastern Washington would produce much less dramatic effects.
Washington State, especially the Puget Sound basin, has a history of frequent
earthquakes. More than 1,000 earthquakes are recorded in the state annually.
Large earthquakes in 1949, 1965 and 2001 caused over $1 billion in damages
throughout Puget Sound. The most recent earthquake, the “Nisqually Quake” on
February 28, 2001, was a 6.8 magnitude earthquake located 17.6 kilometers
northeast of Olympia.
Recorded damage sustained to date in Mason County has been relatively minor
and has been restricted to some incidence of cracked foundations, walls and
chimneys, and damage to wells.
Effects of a major earthquake in the Puget Sound basin area could be
catastrophic, providing the worst-case disaster short of drought-induced wild fire
sweeping through a suburban area. Hundreds of residents could be killed and a
multitude of others left homeless.
In Mason County, depending on the time of day and time of year, a catastrophic
earthquake could cause hundreds of injuries, deaths and hundreds of thousands
of dollars in property damage.
Seismic Hazard Map
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Deep Earthquakes: The three most recent damaging earthquakes in
Washington, in 2001 (magnitude 6.8, near Olympia), 1965 (magnitude 6.5,
located between Seattle and Tacoma), and in 1949 (magnitude 7.1, near
Olympia), were roughly 40 miles deep and were in the oceanic plate where it lies
beneath the continent. Each earthquake caused serious damage, and was felt as
far away as Montana. No aftershocks were felt following the 1965 and 1949
earthquakes, and only 2 small aftershocks were felt after the 2001 quake. Other
sizable events which were probably deep occurred in 1882, 1909, and 1939.
Shallow Crustal Earthquakes: The largest historic earthquake in Washington or
Oregon occurred in 1872 in the North Cascades. This earthquake had an
estimated magnitude of 7.4 and was followed by many aftershocks. It was
probably at a depth of 10 miles or less within the continental crust. Many other
crustal sources in Washington and Oregon could also produce damaging
earthquakes. Recent studies have found geologic evidence for large shallow
earthquakes 1,100 years ago within the central Puget Basin. Massive block
landslides into Lake Washington, marsh subsidence and tsunami deposits at
West Point in Seattle, tsunami deposits at Cultus Bay on Whidbey Island, and
large rock avalanches on the southeastern Olympic Peninsula have all been
dated to approximately 1,100 years ago.
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Subduction Zone Earthquakes: Although no large earthquakes have happened
along the offshore Cascadia Subduction Zone since our historic records began in
1790, similar subduction zones worldwide do produce "great" earthquakes -
magnitude 8 or larger. These occur because the oceanic crust "sticks" as it is
being pushed beneath the continent, rather than sliding smoothly. Over hundreds
of years, large stresses build which are released suddenly in great earthquakes.
Such earthquakes typically have a minute or more of strong ground shaking, and
are quickly followed by damaging tsunamis and numerous large aftershocks. The
Alaskan earthquake of 1964 was a great subduction zone earthquake. Geologic
evidence shows that the Cascadia Subduction Zone has also generated great
earthquakes, and that the most recent one was about 300 years ago.
LIDAR Mapping
Lidar is an acronym for “light detection and ranging.” In the mapping industry,
this term is used to describe an airborne laser profiling system that produces
location and elevation data to define the surface of the earth and the heights of
above-ground features. Mounted on either a helicopter or a fixed-wing aircraft,
lidar systems use the near-infrared portion of the electro-magnetic light spectrum
(1064 nm) to collect data night or day, in shadow, and beneath clouds. Using
semi-automated techniques the “raw” lidar data is processed to generate a
number of useful end products, including an accurate “bare-earth” terrain model
in which trees, vegetation, and manmade structures have been edited out
How does it work? Lidar systems vary by manufacturer, but all use the
following instrumentation: a laser source and detector; a scanning mechanism
and controller; airborne GPS and IMU equipment; a high-accuracy, highresolution
clock for timing laser emissions, reflections, GPS/IMU, and scan-angle
measurements; high performance computers; and high capacity data recorders.
With these components, lidar data collection is possible:
• A pulse of laser light is emitted and the precise time is recorded
• The reflection of that pulse from the surface is detected and the precise
time is recorded
• Using the constant speed of light, the time difference between the
emission and the reflection can be converted into a slant range distance
(line-of-sight distance)
• With the very accurate position and orientation of the sensor provided by
the airborne GPS and inertial measurement unit (IMU) data, the XYZ
coordinate of the reflective surface can be calculated
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Three Hillshaded Lidar Maps
A large-scale figure at the top shows the location of uplifted shoreline in Case
Inlet and the fault scarps along the projections of the Tacoma Fault. The smallscale
figure in the middle shows two possible fault scarps, a larger east/west
trending scarp that cuts across the larger scarp. A small-scale lidar figure at the
bottom shows a detailed view of the landscape along the Catfish Lake scarp, and
clearly shows a north-side-up scarp trending east/west from Prickett Lake to
Catfish Lake.
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Conclusions
Mason County will experience major earthquake effects. Mitigation efforts must
be instituted and maintained to decrease potential problems from major
earthquakes. They are:
• Examination, evaluation and enforcement of effective building and zoning
codes.
• Public education on what to do before, during and after an earthquake.
• Development of appropriate County and City government response plans.
Response should include detailed immediate action to save resources
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Resources
such as water and gas supplies. Plans should be realistically exercised at
the County and City levels to insure workability and relevance to disaster
response.
United States Geological Survey
University of Washington Geophysics Program
Washington State Department of Natural Resources
Washington State Department of Transportation
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FLOODING
Definition: An inundation of dry land with water.
Flooding is the most common hazard occurring in Mason County. Heavy,
prolonged rain in the fall, winter or spring months often results in saturated
ground and high stream flows. Due to ground saturation, Mason County
businesses and homes located in low-lying areas tend to flood during prolonged
periods of rain.
• River building floods: River building floods are caused by heavy,
prolonged rain, melting snow, or both. Prolonged heavy rains and high
freezing levels are the common cause for river flooding in Mason County.
Runoff from the melting of low elevation snow often contributes to these
floods.
• Tidal floods: Tidal floods occur when high tides, strong winds, heavy
swell, and low atmospheric pressure combine to produce flooding.
• Flash floods: Flash floods are characterized by a very rapid quick rise of
the water level in a small river, stream or dry wash. In the most extreme
case, a flash flood is a literal wall of water moving down a steep canyon or
ravine. The brief intense rainfall from a thunderstorm is usually the cause
of a flash flood. The Skokomish River is considered to be a flash flood
river.
Tidal changes from Hood Canal combined with increased runoff from the
Olympics have produced a history of frequent flooding. The Skokomish River has
recently been identified as a “flash flood” river.
History
Mason County issued disaster or emergency declarations for flooding in 1964,
1974, 1975, 1979, 1990, 1994, 1995, 1996, 1997, 2003, 2006 and 2007.
Historically, flooding occurs to some extent in Mason County every year. Hood
Canal and Puget Sound beaches are often affected by flood tides compounded
by heavy rainfall and high tides.
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Hazard Identification and Vulnerability Assessment
Much of the recent development in the County has occurred either in or near
flood plains. This development increases the likelihood of flood damages in two
ways. First, new developments near a flood plain add structures and people in
flood areas. Secondly, new construction alters surface water flows by diverting
water to new courses or increases the amount of water that runs off impermeable
pavement and roof surfaces. This second effect diverts waters to places that
were previously safe from flooding.
In years past, people living on or near rivers have taken it upon themselves to
remove gravel deposits thus helping to maintain river and stream channels. As
greater emphasis has been placed on maintaining salmon spawning areas, this
type of activity is now restricted and requires hydraulic permits for any activity in
the riverbeds. As a result, deposits of gravel have built up over the years, and
the river channels have become increasingly shallow, exacerbating the chances
of flooding. Low dikes constructed along the Skokomish failed in the December
2007 winter storm.
Mason County will always be vulnerable to flooding, especially in Skokomish
Valley, Tahuya River Valley and along the Satsop River.
Conclusions
Mitigation involves flood plain planning, buyout of flood prone residences,
elevation of homes and management coordinated by local, state and federal
agencies. Building codes and regulations applied to structures aid in mitigation.
Residents should have access to information on flood insurance. Where building
has already occurred on flood plains, emergency preparedness in the form of
sandbags, building materials, 3-day evacuation kits and alternate shelter should
be part of each resident's preparation for possible flooding.
Resources
Federal Emergency Management Agency
National Weather Service
United States Army Corps of Engineers, Northwest Division
Washington State Emergency Management Division
Western Regional Climate Center
Attachments
Skokomish River Basin Map
Tahuya River Basin Map
Satsop River Basin Map
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ATTACHMENT I
SKOKOMISH RIVER BASIN
20

ATTACHMENT II
TAHUYA RIVER BASIN
21

ATTACHMENT III
SATOP RIVER BASIN
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FIRES - FOREST, WILDLAND, URBAN INTERFACE
Definition
Forest and wildland fires are the uncontrolled destruction of forested and
wildlands by fire caused by natural or human-made events. Forest and wildland
fires occur primarily in undeveloped areas.
Interface fires are a recent phenomenon that occurs in developed forest and
wildlands, only partially cleared, and occupied by structural development. In
interface fires people, homes and small businesses intermingle with the wildland
and forest areas.
When weather conditions are dry and fuels are abundant, rapidly spreading fires
can cause significant loss of life and property.
Forest fires and urban interface fires are possible in Mason County. Sources of
ignition include lightning, arson, recreational activities, debris burning by
individuals or logging companies and carelessness with fireworks. Individuals
cause about 80% of forest fires with about 20% attributed to natural causes.
With much of the County in various stages of forestation, nearly all areas are
vulnerable to fire. Many individual homes and developments border forestland.
Drought conditions often increase the fire danger in early fall. Recent history of
fires in the County indicate that most were human-caused and extinguished
before major damage occurred.
Forest products help sustain the Mason County economy. Forest fires would
result in the loss of timber resources, wild life habitats, watersheds and
recreational areas as well as increased vulnerability to flooding and landslides.
History
It is difficult to trace the fire history of this area back more than 350 years.
However, old-growth trees and fire scars suggest fires about 450, 480, 540, and
670 years ago. Historically, wildland fires were not considered a hazard. Fire is a
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normal part of most forest and range ecosystems. Fires historically burned on a
fairly regular cycle.
The burning cycle in western Washington appears to be about every 100 – 150
years. A preponderance of evidence, however, has been obliterated by logging,
major windstorms that toppled older trees, and more recent fires in the area.
Recorded history of fires in the area, however, indicate Mason County has had
an active history of fires. As communities expand farther and farther into forested
lands, and the desire to maintain the wilderness ambiance, interface fires are
becoming a significant hazard, having the potential for loss of life and destruction
of property.
The last major fire in Mason County burned 800+ acres in the fall of 2006. The
Bear Gulch Fire was confined to the Olympic National Forest in the area of Lake
Cushman.
Bear Gulch Fire, Lake Cushman
Hazard Identification and Vulnerability Assessment
Mason County's forests will remain vulnerable to forest and wild land fires. The
probability of forest and wild land fires will continually change depending on
variables such as drought effects, lightning strikes, careless campers, etc.
Mason County’s fire season usually runs from mid-May through October. Any
prolonged period without significant precipitation presents a potentially
dangerous situation, particularly if strong dry, east winds prevail. The probability
of a forest fire or an interface fire in any one location depends on fuel conditions,
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topography, the time of year, the past weather conditions, and if there is human
activity such as debris burning, camping, etc., which are taking place.
Conclusions
The following steps should be accomplished to preclude major loss of life and
reduce the actual number of fires and hazard areas:
• Since the majority of fires are started by humans, fire prevention education
and enforcement programs can significantly reduce the number of human
started fires.
• An effective early fire detection program and emergency communications
system are essential. The importance of immediately reporting any forest
fire must be impressed upon local residents and people utilizing the forest
areas.
• An effective warning system is essential to notify local inhabitants and
visitors in the area of the fire. An evacuation plan detailing primary and
alternative escape routes is also essential.
• Fire-safe development planning by County and City government planners
is essential.
• Encourage citizens to incorporate defensible space planning when
landscaping their property.
• Road criteria should ensure adequate escape routes for new sections of
development in forest areas with both ingress and egress planned.
• Road closures should be increased during peak fire periods to reduce the
access to fire prone areas.
Resources
National Weather Service
USDA Forest Service
Washington State Department of Natural Resources
Washington State Patrol, Fire Protection Bureau
25

LAND SHIFT (SLIDES / EROSION)
Definition
The term landslide refers to the down-slope movement of masses of rock and
soil. Slides range in size from thin masses of soil a few yards wide to deepseated
bedrock slides.
Slides are commonly categorized by the form of initial failure, but they may travel
in a variety of forms along their paths. This travel rate may range in velocity from
a few inches per month to many feet per second, depending largely on slope,
material and water content. The recognition of ancient, dormant slide masses are
important as they can be reactivated by earthquakes or unusually wet winters.
Also, because they consist of broken materials and disrupted ground water, they
are more susceptible to construction-triggered sliding than adjacent undisturbed
material.
Erosion refers to the gradual removal of soil through wind or water action.
Erosion may be induced or increased by failure to use ground covers to protect
soil from wind or drainage systems that allow good dispersal of storm water.
Slopes on waterfront can also be severely undercut by normal wave action or
large waves produced by storms.
History
Mason County is subject to landslide or soil erosion due to wind, water and
flooding at all times of the year. Mason County's most recent history, the winter
storm of 2007, caused both Highways 101 and 106 to close several times in the
vicinity of Lilliwaup, Eldon and Union. The Tahuya Peninsula was severely
impacted by landslides. Millions of dollars in damage was caused by landslides
and erosion during this storm.
Hazard Identification and Vulnerability Assessment
There are 3 broad categories of landslides that commonly occur in Mason
County:
• Debris flows are the most hazardous to life. They are fast moving, watersaturated
masses of soil, rock, and debris (tree trunks, limbs, etc.) that
move down steep slopes and channels. Debris flows are typically
triggered by intense rainfall, and can run long distances when confined to
a channel.
• Shallow landslides occur within the sliding surface is located within the soil
mantle or weathered bedrock. They usually include debris slides, debris
flow, and failures of road cut-slopes. Landslides occurring as single large
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locks of rock moving slowly down slope are sometimes called block
glides.
• Deep-seated landslides are slides in which the sliding surface is mostly
deeply located below the maximum rooting depth of trees. Deep-seated
landslides usually involve loose dust, soil, broken / weathered rock, and/or
bedrock and include large slope failure associated with translational,
rotational, or complex movement.
CONCLUSIONS
Washington is one of seven states listed by the Federal Emergency Management
Agency as being especially vulnerable to severe land stability problems.
Earthquakes combined with heavy precipitation may increase risk for those
previously thought to be on stable ground.
With population increasing and demanding “view” property and tree removal to
be able to “see the view” there is increasing risk of landslides in residential areas.
Those buildings on steep slopes and bluffs are at risk in seasons of heavy rains
or prolonged wet spell. The property below the landslide is also at risk.
Landslide, mudflow and debris flow problems are often complicated by problems
of land management. By studying the effects of landslides in slide-prone regions,
plans for the future can be made and the public may be educated to prevent
development in vulnerable areas. Applying established ordinances where
geological hazards have been identified will prevent some landslide losses.
However, Mason County already has many areas above or below unstable
slopes that have established houses and businesses. Careful maintenance of
vegetation on slopes, prevention of erosion, and engineered drainage of slopes
and mitigation using qualified expertise is necessary to protect these areas.
RESOURCES
Federal Emergency Management Agency
National Weather Service
United States Army Corps of Engineers
Washington State Department of Natural Resources
Washington State Department of Ecology
ATTACHMENTS
Highway 101 Major Slide Areas
Major Slide Areas Along North Shore Road
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HIGHWAY 101 MAJOR SLIDE AREAS
(South to North)
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MASON SLIDE AREAS ALONG NORTH and SOUTH SHORE ROADS
(East to West)
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SLIDE AREAS ALONG HIGHWAY 3
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PICKERING PASSAGE SLIDE AREAS
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HARSTEME ISLAND SLIDE AREAS
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SKOOKUM INLET SLIDE AREAS
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SEVERE STORMS
Definition
Severe storms are atmospheric disturbances usually characterized by strong
winds, frequently combined with rain, snow, sleet, hail, ice, and thunder and
lightning.
• Hail storms occur when freezing water in thunderstorm type clouds
accumulates in layers around an icy core. Hail causes damage by
battering crops, structures, automobiles, and transportation systems.
When hailstones are large (especially when combined with high winds),
damage can be extensive.
• An ice storm occurs when rain falls out of the warm, moist, upper layer of
atmosphere into a below freezing, drier layer near the ground. The rain
freezes on contact with the cold ground and other surfaces. It accumulates
on exposed surfaces such as trees, roads, houses, power lines, etc. The
accumulated weight of this ice, especially when accompanied by wind,
can cause damage to trees and utility wires. Ice storms are usually of
short duration from several minutes to a few hours. However, the danger
left behind will last until a rising temperature allows for thawing.
• Snow storms or blizzards, which are snowstorms accompanied by high
wind and/or poor visibility, occur occasionally in the County. A snowstorm
including warmer moist air from the Pacific Ocean overrunning existing
cold subfreezing air could continue to drop snow for several days.
• Windstorms have occurred in Mason County, occasionally causing
extensive damage. The strongest windstorm causing damage throughout
the County was the 1962 Columbus Day Storm, which caused extensive
damage throughout not only Mason County, but the Pacific Northwest
from Northern California to British Columbia.
History
Localized geographic conditions can exacerbate the problem, causing an
increase in wind intensity. Mason County can expect some wind-related
problems on an annual basis, although the majority of those do not cause
extensive damage.
High winds have caused extensive damage through the County in past years.
The most noted storm was the "Columbus Day " (hurricane type) storm of 1962.
Severe winds also occurred during the Inauguration Day storm of 1993. Other
storms that have severely impacted Mason County have occurred in: 1986, 1985,
1980, 1979, 1973, 1971, 2006 and 2007.
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1962 Columbus Day Storm damage - crushed car
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The most severe snowstorms that have occurred in Mason County were: 2008,
1996, 1990, 1985, 1971, 1969, 1961, 1951, 1950 and 1949. Historically, the most
severe storms occur during the autumn and winter months from October through
February.
Snow at the corner of 1st Avenue and
Pike Street, February 1916
Postcard
Snow on Commercial Street (1st Avenue S) looking
north from Main, Seattle, January 1880.
Courtesy Old Seattle Paperworks
In December of 1996 through February 1997 a series of winter storms delivered
snow, freezing rain, warm rain and wind to the west coast producing floods, snow
and ice damage and several landslides.
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Hazard Identification and Vulnerability Assessment
The general effects of most severe local storms are immobility and loss of
electrical power and telephone service. Physical damage to homes and
businesses can occur from wind damage, accumulation of snow, ice, and hail.
Even a small accumulation of snow can wreak havoc on transportation systems
due to a lack of snow clearing equipment and operators.
All areas of the County are vulnerable to various severe local storms. Western
Washington has had an average of 11.4 inches of snowfall annually over the past
30 years. Windstorms generally occur between October and April as well. Power
outages are common as a result of these storms. Road travel is often
treacherous due to snow, ice, and fallen trees. As a result, schools are often
closed and local businesses are impacted. Emergency response is often
delayed.
Conclusions
Local jurisdiction plans should provide a priority for road and street clearance,
provision of emergency services, mutual aid with other public entities, and
procedures for requesting state and federal aid if needed. The public should be
given information on emergency preparedness and self-help to prepare for better
response during severe storms.
Mitigation efforts include effective warning through the media. 3-day
preparedness kits help people weather the storm if they are without normal
utilities and comforts. Well-packed kits could be easily transported if an
evacuation was necessary/possible. For those residents living in elevations
prone to snowstorms, a 14-day preparedness kit is highly recommended. Any kit
should include prescription medications.
Resources
National Oceanic and Atmospheric Administration
National Weather Service
Department of Commerce
Office of Oceanic and Atmospheric Researce
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TSUNAMI, HIGH WAVES, SEICHES
Definitions
Tsunamis are sea waves generated by
seismic activity. There is some debate as
to whether or not a tsunami could be generated in Puget Sound by a local or offshore
earthquake. Underwater volcanic eruptions and landslides can also
generate tsunamis.
High waves, usually caused by wind, and storm activity have battered Puget
Sound in the past so must be considered as a hazard to Mason county.
A seiche, or a sloshing affect much like the splash from getting into a bathtub,
can occur not only on the Sound but on lakes, in reservoirs, etc.
History
Much of Mason County is surrounded by water, from the Puget Sound to the
Hood Canal. With so much shoreline in the County, a tsunami, high waves, or a
seiche would have a devastating affect on Mason County residents. Flooding and
property damage would occur and residents would be displaced.
Conclusions.
Earthquakes and other underwater disturbances will occur and can cause
general or localized damage from a tsunami or a seiche.
Damage from a tsunami or a seiche may range from insignificant to catastrophic,
however, there is no historical data indicating major damage from a Seiche in
Puget Sound or Hood Canal.
Seiches that could occur in Mason County have the potential to cause property
damage and casualties. Public education on tsunamis and seiches is normally
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included in disaster preparedness classes. Although much work has been done
on disaster preparedness for public, local governments, emergency planners and
the citizens, they need to recognize the dangers and effects of tsunamis and
seiches as a component of the earthquake hazard.
Resources
National Oceanic and Atmospheric Administration
National Weather Service
United States Geological Survey
Washington State Department of Natural Resources
49

VOLCANOS/ASH FALL
Definition
A volcano is a vent in the earth’s crust
through which magma, rock fragments,
gases, and ash are ejected from the
earth’s interior. A volcanic mountain is
created over time by the accumulation
of these erupted products on the
earth’s surface.
History
There are no volcanoes in Mason County, however, the proximity to potentially
active volcanoes in the Cascade Mountains to the east could impact the county.
When Mt. St. Helens erupted on May 18, 1980, heavy ash from a west wind
blanketed much of Eastern Washington. Subsequent eruptions on May 25 and
June 12 similarly affected Western Washington, although to a lesser degree. Fifty
seven people were killed during this 5.1 magnitude eruption.
Mount Rainier volcano in Washington State is one of the Nation’s most
dangerous volcanoes. More than 100,000 people live in areas near Rainier that
have been buried by volcanic debris flows during the past few thousand years.
Mason County’s location with respect to the active volcanoes would limit the
number of volcano hazards, however impacts would be felt. The economic,
cultural and transportation impacts that would be experienced in Mason County,
however, would be severe if such an eruption were to occur on Mount Rainier.
Interstate 5 and Interstate 90 would be closed, thus disrupting key routes for
trade and travel.
Ash and some debris could fall on Mason County depending on prevailing winds
at the time. The County could serve as a site for displaced residents for not only
days, but perhaps for decades to come, thus impacting the infrastructure and
resources. Puget Sound fishing resources and economic foundations of the
timber and recreation industries could be impacted for decades. The tourism
industry and economic benefits derived could also be affected for Mason County.
Hazard Identification and Vulnerability Assessment
Volcanoes commonly repeat their past behavior. It is likely that the types,
frequencies, and magnitudes of past activity will be repeated in the future.
Volcanoes usually exhibit warning signs that can be detected by instruments or
observations before erupting. However, explosions caused by heated material
coming into contact with ground water can happen without warning. In the future
Washington State can expect volcanoes avalanches, lahars (mudflows), lava
flows, pyroclastic flows, and tephra falls, and collapse of a sector of a volcano
50

within the Cascade Range. Valleys are vulnerable to lahars, volcanic debris
flows, and sedimentation, which can destroy lakes, streams, and structures.
Areas downwind of a volcano eruption are vulnerable to reduced visibility, ash
fall, and caustic gases. Some of the after effects of a volcanic eruption are:
• Avalanches of glacial ice, snow, rock, and debris from volcanic mountains cause
damage down slope and in valleys. Avalanches can occur without warning, travel
rapidly, and carry large amounts of material.
• Lahars or volcanic mudflow originate from volcanic landslides or from the
eruption of melted water. Lahars move faster on the steep slopes nearest their
source, and attain speeds of 15 to 60 miles per hour. The highest speed
measured on the slopes of Mount St. Helens was 90 miles per hour. Lahars
attain depths of hundreds of feet in the canyons near their origin and spread out
over valleys downstream. A large volume lahar may overtop or destroy a dam by
suddenly displacing water or creating huge waves.
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• Magma or molten rock or lava originates from the
main cone or cinder cone of a mountain. Cascade
Range volcanic magma flows have been short and
slow moving. The heat of the magma may start
forest or grass fires. Flows bury roads and escape
routes. Magma flows bury roads and escape
routes.
• Pyroclastic flow is composed mainly of volcanic rock and
dense ash material and is ejected from an exploding
volcano. In contrast to the slow moving lava flow,
pyroclastic flow moves at speeds up to 200 miles an hour.
The result is a tremendous amount of rock traveling down
steep slopes at great speeds. Humans in the path of a
pyroclastic flow would not survive.
• Tephra falls are from explosive eruptions that blast fragments of rock and ash
into the air. Large fragments fall to the ground close to the volcano. Small
fragments and ash can travel thousands of miles downwind.
• Steam and gas explosions containing pulverized lava and rock fragments
bombard areas as far away as 10 miles. Steam explosions occur any time that
hot material comes into contact with water, glacial ice, or snow. No eruptive
activity is necessary for this to occur.
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• Clouds of carbon dioxide and toxic gases kill vegetation and animals with
chemical poisons, internal or external burns, and asphyxiation.
• Ash falls are harsh, acidic, gritty, smelly, and causes lung damage to the young,
old, or people suffering from respiratory problems. When atmospheric sulfur
dioxide combines with water it forms diluted sulfuric acid that causes burns to
skin, eyes, mucous membranes, nose, and throat. Acid rains affect water
supplies, strip and burn foliage, strip paint, corrode machinery, and dissolve
fabric.
Volcanic ash particles are very small in size
and have a vesicular structure with numerous cavities
• Heavy ash falls blots out light. Heavy demand for electric light and air
conditioning cause a drain on power supplies. Ash clogs waterways and
machinery. It causes electrical short circuits, drifts into roadways, railways,
and runways. Very fine ash is harmful to mechanical and electronic
equipment. The weight of ash causes structural collapse, particularly when
it becomes water saturated. Because it is carried by winds it continues as
a hazard to machinery and transportation systems for months after the
eruption.
Ash from Mount St. Helens—Yakima, Wash., May 1980.
• Volcanic earthquakes occur within a volcano. Earthquakes from local
tectonic sources or shallow faults in the earth's crust can also shake a
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Conclusion
volcano. Examples of such earthquakes include the "St. Helens seismic
zone" and "West Rainier zone." All Washington State volcanoes are
situated close shallow crustal fault zones.
Volcanoes in Washington State have a history of eruption and will continue to
erupt. Volcanic ash fall is one of the serious consequences of volcanic eruption.
The possibility of significant ash all on Mason County is considered small. An
eruption of the closest dormant volcano, Mount Rainier, is possible, but the
actual effect on Mason County would likely be minor.
County and City government must maintain plans to ensure essential services
are available in the event of significant ash fall.
Resources
National Weather Service
US Department of Agriculture
US Forest Service
US Geological Survey
University of Washington
Washington State Department of Natural Resources
TECHNOLOGICAL HAZARDS
DAM FAILURE
Definition
Dam failure is the uncontrolled release of impounded water resulting in
downstream flooding that can affect life and property. Flooding, earthquakes,
blockages, landslides, lack of maintenance, improper operation, poor
construction, vandalism or terrorism can cause dam failures.
History
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Dam failure has not been a major concern for the residents of Mason County.
There has been no history of lives lost, property loss, or other damage as the
result of dam failure.
Mason County is vulnerable to dam failure. To assure Dam safety, the State
Department of Ecology inspects all dams in Mason County and requires safety
plans from the owner of each dam in the County.
History indicates a low probability of dam failure in Mason County. The failure of
a high hazard dam would threaten an important segment of the County
suggesting moderate vulnerability. Because the major dams within the County
are well maintained and operated it provides no reason to anticipate a
compromise in the structural integrity other than from a major natural disaster or
from terrorist actions there is a low risk assigned.
Hazard Identification and Vulnerability Assessment
Mason County has two publicly owned dam and several privately owned dams.
Cushman Dam No. 1 is a hydroelectric dam on the North Fork of the Skokomish
River in Mason County forming Lake Cushman.
Built on February 12, 1925, its two 21,600 kilowatt generators provide 127 million
kilowatt-hours annually to the Tacoma Power system. Tacoma began the
Cushman project in 1919 because of the demand for electricity following the
economic and housing expansion after World War I to the city of Tacoma.
It has a concrete arch design and includes 90,000 cubic yards (69,000 m³) of
concrete, covering a whole 6,244 feet (1903 m) of water. Construction began on
July 7, 1924 under the commissioner Ira S. Davidsson (1918-1940). It has a top
width of eight feet (2.4 m) and a base width of 50 feet (15 m), at 275 feet (84 m)
high and 1,111 feet (339 m) long. Cushman Dam No. 1 was activated on March
23, 1926, with the push of a button by President Calvin Coolidge in a ceremony
at the White House.
A second, smaller dam, Cushman Dam No. 2, was completed by December
1930. This is a hydroelectric dam on the North Fork of the Skokomish River in
Mason County, Washington, United States, forming Lake Kokanee. Built in 1930,
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its three 27,000 kilowatt generators provide 233 million kilowatt-hours annually to
the Tacoma Power system.
The remaining 14 registered dams are privately owned. Inspections are
conducted by the Department of Ecology. Inspections look not only at the dam,
but also at the downstream development that has taken place to ensure that
encroachment into the area project to be flooded in the event of a dam failure
has not taken place. Such encroachment would change the hazard classification.
These dams were often built many years before stringent requirements were in
place. The State Dam Safety Office is attempting to get these smaller dams on a
schedule for comprehensive inspections and repair as well.
Conclusion
Three state statues deal with safety of dams and other hydraulic structures:
Chapters 43.21A, 86.16, and 90.03 RCW. These laws provide authority to
approve plans for dams but also to inspect hydraulic works and require
appropriate changes in maintenance and operation. Periodic inspections are the
primary tool for detecting deficiencies at dams that could lead to failure. Periodic
inspections help identify dams where significant development has occurred
downstream resulting in the need for more stringent building and planning codes
due to greater population at risk.
Mason County Dams
Name of Dam River or Stream Storage Cap. (acre ft)
Anderson Lake Dam Sherwood Creek 550
Bennettsen Lake Dam Tahuya River 270
Buck Lake Dam Jones Creek 16
Christine Lake Dam Tahuya Rover 140
Courner Dam Deer Creel 2
Cushman Dam #1 N. Fork Skokomish River 478,000
Cushman Dam #2 N. Fork Skokomish River 8,750
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Fawn Lake Dam Puget Sound 640
Lake Leprechaun Dam Cranberry Creek 86
Lake Limerick Dam Cranberry Creek 1,528
Little Twin Lakes Dam Campbell Creek 104
Melbourne Lake Dam Eagle Creek 238
Rosand Dam Johns Creek 15
Timberlakes Dam Campbell Creek 904
Udenberg Dam Goldsbourough Creek 150
West Lake Dam Skokomish River 300
ENERGY EMERGENCY
Definition
Energy emergencies may involve several types of energy resources. Oil
embargos targeting Middle Eastern oil producing nations may arise from world
political situations. Electricity may be interrupted due to drought, earthquake, or
major destruction of power transmission lines. They can develop quickly due to
storms or an earthquake, or they may develop slowly such as when world politics
might produce shortages.
History
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Major petroleum shortages developed during the 1973-74 Middle East oil
embargo and during the Iran embargo in 1979. Minor petroleum shortages
developed during the 1989 Exxon Valdez grounding and during the Persian Gulf
War in 1990-91. The state responded to each emergency. During the shortages
of the 1970s, the state ran a “set-aside” program to allocate scarce oil supplies.
The “set-aside” is the state’s strongest measure available to respond to an oil
shortage.
Electricity shortages occurred in 1973-74 and 1977-78 due to drought conditions,
which resulted in insufficient amounts of water to operate hydroelectric plants.
Winter storms in Mason County have caused yearly electrical power outages for
any where from an hour or less to two to three weeks.
Hazard Identification and Vulnerability Assessment
All areas of Mason County are susceptible to petroleum, electrical, and natural
gas shortages.
Mason County is vulnerable to many localized, short-term energy emergencies,
brought about by numerous disasters such as wind and ice storms. Most of these
emergencies are handled by the affected utilities.
Major effects of energy shortages include inconvenience to consumers, reduced
heating and lighting capability, reduced production in all sectors, potential failure
of transportation, water and waste, communication, information, and banking
systems. Energy emergencies can seriously hamper emergency response
capabilities and should be planned for at both the local and state level.
Fuel shortages can occur at any time. However, most oil shortages are due to
the inability of local distribution systems to meet rapidly increasing demand
brought about by panic buying and hoarding. These shortages can be averted by
encouraging normal purchasing practices. Countywide fuel shortages are less
likely.
Natural gas shortages typically occur during cold weather and historically have
meant curtailment for industries. In the future, as natural gas use continues to
grow, and if it takes off as an alternative transportation fuel Mason County’s
pipeline capacity may be insufficient to meet demand. If new capacity lags
demand, shortages could develop.
Conclusions
Future energy shortages are likely to occur due to numerous uncontrollable
factors. The Washington State Energy Office developed a Petroleum Products
Contingency Plan and an Electricity Load Curtailment Plan for managing major
shortages of energy.
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Consumers should be educated on the need for prudent use of all types of
energy resources, and available conservation measures should be utilized
whenever possible.
Resources
Washington State Department of Community, Trade and Economic Development
Washington State Department of Ecology
Washington State Department of Transportation
Washington State Utilities and Transportation Commission
HAZARDOUS MATERIALS
Definition
Hazardous materials are materials, which, because of their chemical, physical, or
biological nature, pose a potential risk to life, health, or property when released.
A release may occur by spilling, leaking, emitting toxic vapors, or any other
process that enables the material to escape its container, enter the environment,
and create a potential hazard. The hazard can be explosive, flammable,
combustible, corrosive, reactive, poisonous, toxic materials, biological agents,
and radioactive.
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History
Hazardous material incidents are intentional and/or unintentional releases of a
material, that because of their chemical, physical, or biological nature, pose a
potential risk to life, health, environment, or property. Each incident’s impact and
resulting response depend on a multitude of interrelated variables that range
from the quantity and specific characteristic of the material to the conditions of
the release and area/population centers involved. Releases may be small and
easily handled with local response resources or rise to catastrophic levels with
long-term consequences that require representatives of federal, state, and local
governments to be present at the scene, with each level consisting of personnel
from between five and 15 different agencies.
The Washington State Hazardous Materials Program consists of several
agencies, each responsible for specific elements of the program. A number of
strategies have evolved to limit risk, response to, and recovery from hazardous
materials releases, intentional discharges, illegal disposals, or system failures. A
comprehensive system of laws, regulations, and resources are in place to
provide for technical assistance, environmental compliance, and emergency
management.
Federal and state statutes require a Local Emergency Planning Committee
(LEPC) to develop and maintain emergency response plans based on the
volumes and types of substances found in, or transported through, their districts.
Conclusion
The state developed and adopted standardized hazardous materials emergency
response training. Training and supporting materials are available to all public
emergency responders. The Washington State Departments of Ecology, Health,
Transportation, and the Washington State Patrol maintain hazard identification,
vulnerability analysis, and risk analysis documentation and databases for
hazardous materials incident.
Resources
United States Environmental Protection Agency
Washington State Department of Ecology
Washington State Department of Health
Washington State Department of Transportation
Washington State Patrol
Washington State Emergency Management Division
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TIER II REPORTS
TO BE ADDED
62