Untitled - Ohio Insurance Institute

Tornadoes
are dangerous
A tornado’s strength is hard to imagine, but it can spin at speeds exceeding
200 mph as it moves across land. Never try to outrun a tornado,
since it can change direction in an instant. The best thing to do if a
tornado is sighted is to seek safe shelter immediately.
l HOW TORNADOES ARE FORMED
Tornadoes form when cold, dry air meets with warm, moist air. A whirlwind
is created by the gust of warm air rising in a spiral motion, causing
water vapor to be swept upward. As the warm air cools, a twisting,
spiral-shaped cloud forms. This funnel cloud is what we know as a
tornado.
Cold air whirls around the outside of the funnel, causing a roar that
often sounds like a loud freight train. Air pressure inside the tornado is
very low, as if there is a hole in the air. Outside, air spins into the hole
carrying with it anything in its path. The tornado travels as it spins.
A tornado usually lasts only minutes. Thunderstorms create the
energy that feeds tornadoes. As the rain accompanying a tornado falls
to earth, it cools the land. The tornado weakens as the steady supply of
warm, moist, rising air dies out. The spinning motion slows down as the
heated air is no longer pushed up, and is replaced by the cooler, heavier
inflowing air.
Ohio averages 16 tornadoes and five tornado-related fatalities each
year.
l TORNADO FACTS
• Ohio’s tornado activity has been below average for the past few
years. Four tornadoes were reported in 2005, causing no injuries or
deaths. Ohio’s eight tornadoes in 2004 caused one injury and no
deaths; while 12 tornadoes resulted in 18 injuries in 2003. Ohio’s
tornado activity in 2002 was above average—22 tornadoes resulted
in 16 injuries and five deaths. Ohio’s worst year for tornadoes was
1992 when 60 tornadoes were confirmed. Texas holds the record for
the greatest number—178 tornadoes occurred in the Lone Star state
in 2004.
NOTE: (Additional tornado statistics can be found online at www.
weathersafety.ohio.gov.)
• Tornadoes are usually accompanied by hail, severe thunderstorms
and wind. Ohio experiences thunderstorm activity an average of
30–50 days annually.
• Severe Weather Awareness Week in Ohio is held annually, usually
in March, to serve as a reminder to “brush up” on safety precautions
prior to the height of severe weather season.
• Most tornadoes occur during spring and summer months in the late
afternoon on a hot day. Nationally, the peak months tend to be May,
June and July. About one in every four tornadoes occurs between
4–6 p.m. Peak season in Ohio is April through mid-July, with most
occurring between 2–10 p.m. But, tornadoes can strike anywhere, at
anytime of day or night. Ohio experienced damage-causing tornadoes
in November 2002 and 2003.
• A “waterspout” is a tornado over the water. Tornadoes are also
known as cyclones, twisters and funnel clouds.
• Over the 10-year period, 1996–2005, the US averaged 1,278 tornadoes
and 58 tornado-related deaths per year. In the prior 10 years
(1986–1995), the US averaged 1,003 tornadoes and 42 deaths per
year. A record-breaker occurred in 2004 when 1,819 tornadoes
touched down in the US, which caused 36 deaths.
l POINTS TO COVER
• How a tornado is formed
• Why a tornado is dangerous
• When Ohio tornadoes usually occur
• The purpose of Severe Weather Awareness Week
l ACTIVITIES
1. Obtain two-2 liter pop bottles. Fill one with water. Connect the tops
of the bottles, using a washer and duct tape, or purchase a “Tornado
Tube” from a science or teacher supply store or online. Tip the full
bottle upside down and swirl the water to drain into the empty
bottle. The result depicts how a tornado forms.
2. Fill a mayonnaise or mason jar with water. Make the water swirl by
stirring it with a spoon. Drop in a few drops of food coloring or ink.
Another way to make a tornado in a bottle is to mix water, food
coloring and a few drops of liquid soap in a quart jar. Tightly cap the
jar. Give the jar a quick twist with both hands and watch the vortex
appear in the jar.
3. To depict a tornado’s force: Get a potato and a plastic drinking straw.
Hold the straw against the potato, and apply pressure (more than
likely the straw will bend and not penetrate the potato). Now, hold
the potato in one hand, and the straw in the other about 2 feet apart.
Thrust the straw into the potato (it should penetrate depicting the
force of wind). The greater the velocity of matter, the greater its momentum.
The faster you make the straw move, the greater its force
when it strikes the potato and the deeper it will penetrate. The force
of a tornado has been known to drive straws right through boards!
4. Additional activity resources
• Scholastic http://teacher.scholastic.com/activities/wwatch/
tornadoes/experiments.htm
• Weather Wiz Kids (includes other types of weather experiments
too) http://www.weatherwizkids.com/WxExperiments.htm
• National Geographic Kids http://www.nationalgeographic.com/
ngkids/trythis/trythis_water/bottled-vortex.html
• Ohio EMA Disaster Detectives http://www.ema.ohio.gov/kids_
page/index.htm
be prepared
It’s important that students know the difference between a tornado
“watch” and “warning.”
• A Tornado WATCH means a tornado could occur—the climatic conditions
are right for a tornado. When a watch is issued, be prepared
to seek shelter and stay tuned to the radio or television for weather
updates. Or, listen to the National Weather Service updates on a
weather radio.
• A Tornado WARNING is your signal to SEEK SHELTER IMMEDIATELY
—this means a tornado has been sighted in the area. The National
Weather Service, which tracks storms on radar, will issue a tornado
WATCH or WARNING as needed. Whenever there is danger of a tornado,
it’s very important that you are prepared to act quickly. Some
communities have special sirens to warn of an approaching tornado.
Radio and television stations will broadcast information about severe
weather through special weather bulletins and newscasts.
Encourage your students to participate in the Ohio Committee for Severe Weather Awareness Annual Poster Contest
Download details & entry requirements at www.weathersafety.ohio.gov
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