SAFETY RULES TO SURVIVE THE WEATHER

Tornado, nature's most fierce violent storm, is a violently rotating column of air in contact with the ground.

Tornado Watch:

Means tornadoes and severe are possible.

Tornado Warning:

Means a tornado has been detected or seen, is on the ground and moving.

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. If caught outside or in a vehicle, lie flat in a nearby ditch or depression.
• Mobile homes, even if tied down, offer little protection from tornadoes and should be abandoned.

Occasionally, tornadoes develop so rapidly that advance warning is not possible. Remain alert for signs of an approaching tornado. Flying debris from tornadoes causes most deaths and injuries.

Tornado safety in schools:

• Develop a severe weather action plan and have frequent drills.
• Each school should be inspected and tornado shelter areas designated by a registered engineer or architect. Basements offer the best protection. Schools without basements should use interior rooms and hallways on the lowest floor and away from windows.
• Those responsible for activating the plan should monitor weather information from NOAA Weather Radio and local radio/television.
• If the school's alarm system relies on electricity, have a compressed air horn or megaphone to activate the alarm in case of power failure.
• Make special provisions for disabled students and those in portable classrooms.
• Make sure someone knows how to turn off electricity and gas in the event the school is damaged.
• Keep children at school beyond regular hours if threatening weather is expected. Children are safer at school than in a bus or car. Students should not be sent home early if severe weather is approaching.
• Lunches or assemblies in large rooms should be delayed if severe weather is anticipated. Gymnasiums, cafeterias, and auditoriums offer no protection from tornado-strength winds.
• Move students quickly into interior rooms or hallways on the lower floor. Have them assume the tornado protection position shown here.

You can prepare for the possibility of a tornado by learning the safest places to seek shelter when at home, work, school, or outdoors. You should also understand basic weather terms and danger signs related to tornadoes. Your chances of staying safe during a tornado are greater if you have a plan for you and your family, and practice the plan frequently.

National Weather Service Preparedness Guide

Thunderstorms, Tornadoes, Lightning Preparedness Guide: This preparedness guide from the National Weather Service explains thunderstorms and related hazards and suggests life-saving actions you can take. With this information, you can recognize severe weather, develop a plan, and be ready to act when threatening weather approaches. Remember...your safety is up to you. Click on the image to view or download preparedness guide.

The Fujita Tornado Scale (F Scale)

Wind speeds in tornadoes range from values below that of hurricane speeds to more than 300 miles per hour! Unlike hurricanes, which produce wind speeds of similar values over relatively widespread areas (when compared to tornadoes), the maximum winds in tornadoes are often confined to extremely small areas, and vary tremendously over very short distances, even within the funnel itself. The tales of complete destruction of one house next to one that is totally undamaged are true and well documented.

In 1971, Dr. T. Theodore Fujita of the University of Chicago devised a six-category scale to classify U.S. tornadoes into six intensity categories, named F0-F5. These categories are based upon the estimated maximum winds occurring within the funnel. The Fujita Tornado Scale (or the "F Scale") has subsequently become the definitive scale for estimating wind speeds within tornadoes based upon the damage done to buildings and structures. It is used extensively by the National Weather Service in investigating tornadoes (all tornadoes are now assigned an F scale), and by engineers in correlating damage to building structures and techniques with different wind speeds caused by tornadoes.

The Fujita scale bridges the gap between the Beaufort Wind Speed Scale and Mach numbers (ratio of the speed of an object to the speed of sound) by connecting Beaufort Force 12 with Mach 1 in twelve steps. The equation relating the wind velocities (V in mph) with the F scale (F) is V = 14.1 * ((F+2) to the 1.5 power).

F1 on the Fujita scale is equal to B12 (73 mph) on the Beaufort scale, which is the minimum windspeed required to upgrade a tropical storm to a hurricane. F12 on the Fujita scale is equal to M1 (738 mph) on the Mach numbers. Though the Fujita scale itself ranges up to F12, the strongest tornadoes max out in the F5 range (261 to 318 mph).

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