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FEMA Storm Shelters : Tornado Shelters & Hurricane Safe Rooms

FAQs - Tornado Storm & Shelter

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Tornadoes are nature’s most violent storms. In an average year, 800 tornadoes are reported across the United States, resulting in 80 deaths and over 1,500 injuries. A tornado is as a violently rotating column of air extending from a thunderstorm to the ground. The most violent tornadoes are capable of tremendous destruction with wind speeds of 250 mph or more. Damage paths can be in excess of one mile wide and 50 miles long. Tornadoes come in all shapes and sizes and can occur anywhere in the U.S at any time of the year. In the southern states, peak tornado season is March through May, while peak months in the northern states are during the summer.

Some tornadoes are clearly visible, while rain or nearby low-hanging clouds obscure others. Occasionally, tornadoes develop so rapidly that little, if any, advance warning is possible.

Before a tornado hits, the wind may die down and the air may become very still. A cloud of debris can mark the location of a tornado even if a funnel is not visible. Tornadoes generally occur near the trailing edge of a thunderstorm. It is not uncommon to see clear, sunlit skies behind a tornado.

Tornado safety and preparedness are key to protecting your loved ones during a tornado. Be sure to stay tuned to NOAA Weather Radio for warning instructions; take shelter immediately if a tornado is imminent; go to a designated shelter in a basement or interior room such as a closet or bathroom; if you are in an automobile, mobile home or in the open, seek shelter in a sturdy structure or get down in a ditch or depression; always protect your head and body from flying debris.

Tornado Watch
Tornadoes are possible. Remain alert for approaching storms. Watch the sky and stay tuned to NOAA Weather Radio, commercial radio, or television for information.

Tornado Warning
 A tornado has been sighted or indicated by weather radar. Take shelter immediately.

FEMA - Storm Shetlers - Tornado Shelters, Hurrican Safe Rooms

Category / Typical Tornado Damage

Tornado Category F0: Gale tornado (40-72 mph); light damage. Some damage to chimneys; break branches off trees; push over shallow-rooted trees; damage to sign boards.

Tornado Category F1: Moderate tornado (73-112 mph); moderate damage. The lower limit is the beginning of hurricane wind speed; peel surface off roofs; mobile homes pushed off foundations or overturned; moving autos pushed off the roads.

Tornado Category F2: Significant tornado (113-157 mph); considerable damage. roofs torn off frame houses; mobile homes demolished; boxcars pushed over; large trees snapped or uprooted; light-object missiles generated.

Tornado Category F3: Severe tornado (158-206 mph); Severe damage. Roofs and some walls torn off well-constructed houses; trains overturned; most trees in forest uprooted; heavy cars lifted off ground and thrown.

Tornado Category F4: Devastating tornado (207-260 mph); Devastating damage. Well-constructed houses leveled; structure with weak foundation blown off some distance; cars thrown and large missiles generated.

Tornado Category F5: Incredible tornado (261-318 mph); Incredible damage. Strong frame houses lifted off foundations and carried considerable distance to disintegrate; automobile sized missiles fly through the air in excess of 100 yards; trees debarked; incredible phenomena will occur.

 

Tornado Activity in the United States
Summary of Recorded F3, F4 & F5 Tornadoes per 3,700 Square Miles (1950 - 1998)
Based on NOAA, Storm Prediction Center Statistics

Number of Recorded Major Tornadoes

Areas Affected

< 1

All or most of Washington, Oregon, California, Idaho, Utah, Arizona, Montana, Wyoming, Colorado, New Mexico, Maine, New Hampshire, Vermont and Rhode Island. Parts of North Dakota, Minnesota, Wisconsin, Michigan, Texas, Florida, Delaware, Alaska, Hawaii, American Somoa, Puerto Rico and Virgin Islands. Isolated areas in Massachusetts, New York, Connecticut, Pennsylvania, Maryland, Ohio, Kentucky and Louisiana. Storm Shelter & Tornado Shelter

1 - 5

Most of South Dakota, Virginia, West Virginia, and North Carolina. Parts of North Dakota, Nebraska, Texas, Minnesota, Wisconsin, Michigan, New York, Pennsylvania, Maryland, Washington DC, and South Carolina. Isolated areas in Washington, Oregon, Montana, Wyoming, Kansas, New Mexico, Ohio, Kentucky, Tennessee, Maine, Georgia and Florida. Storm Shelter & Tornado Shelter

6 - 15

Parts of South Dakota, Nebraska, Kansas, Texas, Minnesota, Iowa, Missouri, Wisconsin, Illinois, Mississippi, Ohio, Alabama, and Pennsylvania. Isolated areas of Oklahoma, Arkansas, Louisiana, New Hampshire, Massachusetts, New York, West Virginia, Kentucky, North Carolina, South Carolina, Georgia, and Florida. Storm Shelter & Tornado Shelter

16 - 25

Half of Indiana, parts of Kansas, Texas, Iowa, Kansas, Missouri, Arkansas, Louisiana, Indiana, Kentucky, Tennessee, Mississippi, Alabama and Georgia. Isolated areas in the following states: North Dakota, Minnesota, Wisconsin, Michigan, Louisiana, Michigan, Ohio, Virginia, North Carolina, and South Carolina. Storm Shelter & Tornado Shelter

> 25

Most of Oklahoma, half of Indiana, and isolated areas in the following states: Nebraska, Kansas, Texas, Missouri, Arkansas, Louisiana, Ohio, Kentucky, Tennessee, Mississippi, Alabama and Georgia. Storm Shelter & Tornado Shelter

Q. What is a tornado?

A. A tornado is defined as a violently rotating column of air extending from a thunderstorm to the ground. The most violent tornadoes are capable of tremendous destruction with wind speeds of 250 mph or more. Damage paths can be in excess of one mile wide and 50 miles long. In an average year, 800 tornadoes are reported nationwide.

Q. How do tornadoes form?

A. Before thunderstorms develop, a change in wind direction and an increase in 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. An area of rotation, 2-6 miles wide, now extends through much of the storm. Most strong and violent tornadoes form within this area of strong rotation.

Q. Are there different kinds of tornadoes?

A. Some tornadoes may form during the early stages of rapidly developing thunderstorms. This type or tornado is most common along the front range of the Rocky Mountains, the Plains, and the Western State. Tornadoes may appear nearly transparent until dust and debris are picked up. Occasionally, two or more tornadoes may occur at the same time.

Waterspouts are weak tornadoes that form over warm water. Waterspouts are most common along the Gulf Coast and southeastern states. In the western United States, they occur with cold late-fall or late-winter storms, during a time when you least expect tornado development. Waterspouts occasionally move inland, becoming tornadoes causing damage and injuries.

Q. What should people look for to identify likely conditions for tornadoes?

A. Dark, often greenish sky; large hail; wall cloud; a loud roar, similar to a freight train. Some tornadoes appear as a visible funnel extending only partially to the ground. Look for signs of debris below the visible funnel. Some tornadoes are clearly visible while others are obscured by rain or nearby low-hanging clouds.

Q. When are tornadoes most likely to occur?

A. Tornadoes can happen any time of the year and any time of day. In the southern states, peak tornado season is from March through May. Peak times for tornadoes in the northern states are during the summer. A few southern states have a second peak time for tornado outbreaks in the fall. Tornadoes are most likely to occur between 3 p.m. and 9 p.m.

Q. Who is most at risk during tornadoes?

A. People in automobiles and people in mobile homes; people who may not understand a warning due to a language barrier; the elderly and very young; people with physical or mental impairments.

Q. What dangers other than tornadoes often accompany thunderstorms?

A. Flash floods, lightning, damaging straight-line winds, and large hail.

Q. I live in an area where there are a lot of tornadoes -- what can I do to be prepared ahead of time?

A. The most important steps you can take to protect yourself and your family is to stay tuned to weather forecasts for the most current information, watches and warnings. Have a NOAA Weather Radio with a warning alarm tone and a battery back-up. These special radios can be set up to turn on automatically and alert you when a tornado watch or warning is issued, even when you are sleeping. Listen to radio and television for more information. You should also develop a plan for you and your family so you know where to take shelter at home, at work, at school or when outdoors.

Q. What actions should people take to protect themselves during a tornado?

A. Move to a pre-designated shelter such as a basement in a home or building. 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 cars -- do not try to outrace a tornado. If you're caught outside, lie flat in a nearby ditch or depression.

Q. Should I open my windows before a tornado approaches?

A. It's a myth that open windows equalize pressure and minimize damage when a tornado strikes. Opening windows allows damaging winds to enter the structure. Leave the windows alone and immediately go to a safe Storm Shelter or Tornado Shelter.

Q. Doesn't the low pressure associated with a tornado cause buildings to explode?

A. Violent winds and flying debris slam into buildings and cause most structural damage. Its always safe to stay in Storm Shelter or Tornado Shelter.