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What is a Tornado?

A tornado is a violent windstorm characterized by a twisting, tunnel-shaped cloud. It is spawned by a thunderstorm (or sometimes a result of a hurricane) and produced when cool air overrides a layer of warm air, forcing the warm air to rise rapidly.

Tornado Facts

  • In the U.S., tornado season is generally March through August, although tornadoes can occur at any time of year.
  • They may strike quickly with little or no warning.
  • Over 80 percent of all tornadoes strike between noon and midnight. They can last as little as one minute or over an hour.
  • They may appear nearly transparent until dust and debris are picked up or a cloud forms in the funnel.
  • Injuries or deaths most often occur as buildings collapse, when people are hit by debris, and as people try to escape the storm.
  • According to the National Weather Service, about 42 people are killed because of tornadoes each year.
  • When a tornado is over water, it is called a waterspout.
  • Mobile homes are particularly vulnerable to damage during a tornado. A mobile home can overturn easily even if they are tied down. When a tornado watch is issued, take shelter in a building with a strong foundation.
  • Tornadoes generally occur near the trailing edge of a thunderstorm. It is not uncommon to see clear, sunlit skies behind a tornado.

Know the Terms

Tornado Watch - Issued when conditions are favorable for the formation of tornadoes.
Tornado Warning - Issued when a tornado has been sighted by weather radar.

Danger Zones

  • Although all U.S. states are subject to tornadoes, Alabama, Arkansas, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Louisiana, Mississippi, Missouri, Nebraska, Oklahoma, South Dakota, and Texas are at the greatest risk.

Warning and Danger Signs

  • An approaching cloud of debris can mark the location of a tornado even if a funnel is not visible.
  • Before a tornado hits, the wind may die down and the air may become very still. You may hear the sound of a loud roar, similar to a freight train, or see large hail.

Enhanced Fujita Scale

Actions to Consider


  • Pick a place where family members could gather if a tornado is headed your way. Safe places to consider include a basement, center hallway, bathroom, or closet on the lowest floor. Above all, avoid exterior walls and windows.
  • If you are in a high-rise building, you may not have enough time to go to the lowest floor. Find a place in a hallway near the center of the building.

If at Home

  • Go at once to a windowless, interior room, storm cellar, basement, or the lowest level of the building.
  • Get under and hold onto a piece of sturdy furniture such as a workbench, heavy table, or desk and use your arms to protect your head and neck.
  • Get out and find shelter elsewhere if in a mobile home.

If at Work

  • Go to the basement or to an inside hallway at the lowest level.
  • Avoid places with wide-span roofs such as auditoriums, cafeterias, or large hallways.
  • Get under and hold onto a piece of sturdy furniture and use your arms to protect your head and neck.

If Outdoors

  • Get inside a building or shelter if possible.
  • If shelter is not available or if there is not time to get indoors, lie in a ditch or low lying area and use your arms to protect your head and neck.

If in a Vehicle

  • Never try to outrun a tornado. Get out of the vehicle immediately and take shelter in a nearby building.
  • If there is not time to get indoors, get out of the vehicle and lie in a ditch or low-lying area away from the vehicle. Be aware of the potential for flooding.


  • Check for injuries and provide first aid and CPR if trained to do so.
  • Watch out for broken glass, fallen power lines, and do not enter damaged areas until told it is safe to do so.
  • Do not use candles or an open flame; combustibles may be present.
  • Use caution when entering a damaged building.
  • Report property damage to your insurance agent immediately.

Did You Know...

Tornadoes have been reported in every state in the U.S. and also in every season.

Contact your local or Installation's Office of Emergency Management for more information.