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Spartanburg County Office of
Emergency
Management
Copyright © 2006 "www.scoem.org" · All Rights reserved
Tornado FAQ's
Tornado Background
Answers Each year about a thousand tornadoes touch down in the US. Only a small percentage actually strike occupied buildings, but every year a number of people are killed or injured. The chances that a tornado will strike a building that you are in are very small, however, you can greatly reduce the chance of injury by doing a few simple things. One of the most important things you can do to prevent being injured in a tornado is to be ALERT to the onset of severe weather. Most deaths and injuries happen to people who are unaware and uninformed. Young children or the mentally challenged may not recognize a dangerous situation. The ill, elderly, or invalid may not be able to reach shelter in time. Those who ignore the weather because of indifference or overconfidence may not perceive the danger. Stay aware, and you will stay alive!
When a tornado is spotted, you have only a short
amount of time to make life-or-death decisions. Advance planning and quick
response are the keys to surviving a tornado. Whenever thunderstorms threaten
your area you should listen to local media for latest information/instructions
and keep a watch on the horizon. If you see any revolving funnel-shaped clouds,
report them immediately. A tornado is a violent rotating column of air
extending from a thunderstorm to the ground. The most violent tornadoes can
produce massive destruction with wind speeds of 250 mph or more. Damage paths
can be from 1 mile to 50 miles wide. The typical tornado moves from southwest to
northeast, but they have been known to move in any direction. The average
forward speed of a tornado is 30 mph but it may vary from stationary to 70mph.
Although tornadoes occur in many parts of the world, they are found most
frequently in the United States east of the Rocky Mountains during the spring
and summer months. In an average year, 800 tornadoes are reported nationwide,
resulting in 80 deaths and over 1,500 injuries. Before thunderstorms develop, a change in wind direction along with an increase of wind speed with increasing height creates an invisible, horizontal spinning effect in the lower atmosphere. Rising air within the thunderstorm updraft tilts the rotating air from horizontal to vertical. The area of rotation, 2-6 miles wide, now extends through much of the storm. This rotating column of air, known as a funnel extends from the cloud and grows downward toward the ground. Once the funnel touches the ground is becomes a tornado. Since the center of the funnel is a low pressure area, air rushes into the column and rises. The air is cooled as it rises and water vapor condenses to form the familiar funnel shaped cloud. As the rotating winds begin to pick up dirt and debris from the ground, the funnel will darken. The strongest tornadoes occur in supercell thunderstorms which can also produce large hail and strong downbursts. A tornado watch is issued when conditions are favorable for a tornado to occur. A tornado watch is issued by the National Weather Service when tornadoes are possible in your area. Remain alert for approaching storms. This is time to remind family members where the safest places within your home are located, and listen to the radio or television for further developments. Be prepared to seek shelter.
A tornado warning is
issued when a tornado has been sighted in the area. Immediately seek safe
shelter. In case family
members are separated from one another during a tornado (a real possibility
during the day when adults are at work and children are at school), have a plan
for getting back together. Ask an out-of-state relative or friend to serve as
the "family contact." After a disaster, it's often easier to call long distance.
Make sure everyone in the family knows the name, address, and phone number of
the contact person. Check for gas
leaks--If you smell gas or hear a blowing or hissing noise, open a window and
quickly leave the building. Turn off the gas at the outside main valve if you
can and call the gas company from a neighbor's home. If you turn off the gas for
any reason, it must be turned back on by a professional.
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