- TORNADOES -

Tornadoes are vertical funnels of rapidly spinning air. Their winds may top 250 miles (400 kilometers) an hour and can clear-cut a pathway a mile (1.6 kilometers) wide and 50 miles (80 kilometers) long.

Twisters are born in thunderstorms and are often accompanied by hail. Giant, persistent thunderstorms called supercells spawn the most destructive tornadoes.

These violent storms occur around the world, but the United States is a major hotspot with about a thousand tornadoes every year. "Tornado Alley," a region that includes eastern South Dakota, Nebraska, Kansas, Oklahoma, northern Texas, and eastern Colorado, is home to the most powerful and destructive of these storms. U.S. tornadoes cause 80 deaths and more than 1,500 injuries per year.

A tornado forms when changes in wind speed and direction create a horizontal spinning effect within a storm cell. This effect is then tipped vertical by rising air moving up through the thunderclouds.

The meteorological factors that drive tornadoes make them more likely at some times than at others. They occur more often in late afternoon, when thunderstorms are common, and are more prevalent in spring and summer. However, tornadoes can and do form at any time of the day and year.

Tornadoes' distinctive funnel clouds are actually transparent. They become visible when water droplets pulled from a storm's moist air condense or when dust and debris are taken up. Funnels typically grow about 660 feet (200 meters) wide.

Tornadoes move at speeds of about 10 to 20 miles (16 to 32 kilometers) per hour, although they've been clocked in bursts up to 70 miles (113 kilometers) per hour. Most don't get very far though. They rarely travel more than about six miles (ten kilometers) in their short lifetimes.

Tornadoes are classified as weak, strong, or violent storms. Violent tornadoes comprise only about two percent of all tornadoes, but they cause 70 percent of all tornado deaths and may last an hour or more.

People, cars, and even buildings may be hurled aloft by tornado-force winds—or simply blown away. Most injuries and deaths are caused by flying debris.

Tornado forecasters can't provide the same kind of warning that hurricane watchers can, but they can do enough to save lives. Today the average warning time for a tornado alert is 13 minutes. Tornadoes can also be identified by warning signs that include a dark, greenish sky, large hail, and a powerful train-like roar.

Tornado Safety

What YOU Can Do

Before the Storm:

Develop a plan for you and your family for home, work, school and when outdoors.
Have frequent drills.
Know the county/parish in which you live, and keep a highway map nearby to follow storm movement from weather bulletins.
Have a NOAA Weather Radio with a warning alarm tone and battery back-up to receive warnings.
Listen to radio and television for information.
If planning a trip outdoors, listen to the latest forecasts and take necessary action if threatening weather is possible.


If a Warning is issued or if threatening weather approaches:

In a home or building, move to a pre-designated shelter, such as a basement.
If an underground shelter is not available, move to an interior room or hallway on the lowest floor and get under a sturdy piece of furniture.
Stay away from windows.
Get out of automobiles.
Do not try to outrun a tornado in your car; instead, leave it immediately.
Mobile homes, even if tied down, offer little protection from tornadoes and should be abandoned.

What to do Before a Tornado

Be alert to changing weather conditions.

• Listen to NOAA Weather Radio or to commercial radio or television newscasts for the latest information.

• Look for approaching storms.

• Look for the following danger signs:

◦ Dark, often greenish sky
◦ Large hail
◦ A large, dark, low-lying cloud (particularly if rotating)
◦ Loud roar, similar to a freight train.

If you see approaching storms or any of the danger signs, be prepared to take shelter immediately.

What to Do During a Tornado

If you are under a tornado WARNING, seek shelter immediately!

If you are in:

A structure (e.g. residence, small building, school, nursing home, hospital, factory, shopping center, high-rise building):

Go to a pre-designated shelter area such as a safe room, basement, storm cellar, or the lowest building level. If there is no basement, go to the center of an interior room on the lowest level (closet, interior hallway) away from corners, windows, doors, and outside walls. Put as many walls as possible between you and the outside. Get under a sturdy table and use your arms to protect your head and neck. Do not open windows.

A vehicle, trailer, or mobile home:

Get out immediately and go to the lowest floor of a sturdy, nearby building or a storm shelter. Mobile homes, even if tied down, offer little protection from tornadoes.

The outside with no shelter:

Lie flat in a nearby ditch or depression and cover your head with your hands. Be aware of the potential for flooding.

Do not get under an overpass or bridge. You are safer in a low, flat location.

Never try to outrun a tornado in urban or congested areas in a car or truck. Instead, leave the vehicle immediately for safe shelter.

Watch out for flying debris. Flying debris from tornadoes causes most fatalities and injuries.