ecological characterization atlas of coastal alabama - Data Center

Destruction from storm surge or rise in water level due to strong
sustained winds is likewise mainly restricted to areas fronting the ocean .
Water and wind-driven waves are capable of great devastation, especially when
the surge raises the water level 8 m (25 ft) and waves are driven by 322-kmph
(200-mph) winds, as happened during Hurricane Camille . Surge is more
pronounced in areas where deep water is near shore, as in the area from
Mobile to Panama City, Florida . As the surge moves inland with the storm, a
shallow bottom would cause resistance and reduce the surge . The surge may
also be accentuated in the study area by the funnel shape of Mobile Bay,
which concentrates the surge . When a storm surge occurs during a normal
astronomical high tide, its effect is even greater (Chermock 1976) .
The hurricane surge during Hurricane Frederic in September 1979 is the
highest ever recorded in coastal Alabama (Table 35) . The surge reached a
maximum of 5 .2 m (17 ft) above mean sea level, about 4 .8 km (3 mi) west of
Perdido Bay (Pensacola quadrangle) . The eastern shore of Mobile Bay (Mobile
quadrangle) had high water of 2 .4 to 3 m (8 to 10 ft), while the western
shore (Pensacola and Bay Minette quadrangle) had a high water of 2 .1 to 3 .6 m
(7 to 12 ft) above mean sea level . Further from the open ocean, the Mobile
and Tensaw Rivers (Mobile and Bay Minette quadrangle) had a high water reading
of 1 .4 m(5 .5 ft) . Frederic inundated about 34,800 ha (87,000 acres) in
Mobile and Baldwin Counties . The areal extent of inundation is shown on the
atlas sheets . The shoreline along the Mississippi Sound, Dauphin Island
(Biloxi quadrangle), Ft . Morgan Peninsula, the Gulf Shores area (Pensacola
quadrangle) and the Lower Mobile Delta (Mobile and Bay Minette quadrangle)
were all inundated to some degree by the storm surge . The entire economic
loss attributable to Frederic was approximately $1 .5 billion, economically
one of the most costly hurricanes ever experienced in Alabama (U .S . Army
Corps of Engineers 1981) .
Damage inland from hurricanes is mainly a result of flooding from heavy
rains . After devastating the Louisiana and Mississippi coasts, Hurricane
Camille caused flash floods and landslides in West Virginia and Virginia . In
areas with short stream patterns, the flooding may rapidly' reach a coast
already inundated by a storm surge . In cases where the rain falls far
inland, the flooding may reach the coast after the storm surge recedes and
recovery operations are underway or may flood distant areas not otherwise
affected by the hurricane .
The maximum amount of rainfall from Hurricane Frederic was 23 cm (9
inches) which fell in 24 h at Merrill, Mississippi . Mobile recorded 21 .7 cm
(8 .55 inches) and Dauphin Island recorded 21 .5 cm (8 .45 inches) on 12 and 13
September 1979 (U .S . Army Corps of Engineers 1981) .
Hurricane Camille caused an average of 12 .7 cm (5 inches) of rain across
most of its path, with a maximum recorded rainfall of 26 .9 cm (10 .6 inches)
in Hattiesburg, Mississippi . Camille then brought heavy rains to Alabama and
Tennessee before dumping nearly 68 .6 cm (27 inches) of rainfall in West
Virginia and Virginia (U .S . Army Corps of Engineers 1970) .
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