Tornados

TORNADOS

Conditions are ideal when a mass of warm, moist air becomes trapped beneath cooler, heavier air. Clouds and storms develop in this zone, sometimes causeing a swirling uprush of warm air that is known as a tornado. At first, nothing more than a rounded lobe hangs from the base of the cloud. The lobe gradually elongates and finally touches the ground.

Sometimes, tornados are called twisters.

FUN-FACT: The low pressure causes buildings to actually explode. When a tornado passes, the sudden drop in atmospheric pressure causes air trapped in a building to expand so violently that it literally blows the walls down.

FUN-FACT: One time, it was said that a jar of pickles was blown 25 miles through the air and landed intact.

The Fujita Scale is used to rate the intensity of a tornado by examining the damage caused by the tornado after it has passed over a man-made structure.

THE FUJITA SCALE
F-Scale Number Intensity Phrase Wind Speed Type of Damage Done
F0 Gale tornado 40-72 mph Some damage to chimneys; breaks branches off trees; pushes over shallow-rooted trees; damages sign boards.
F1 Moderate tornado 73-112 mph The lower limit is the beginning of hurricane wind speed; peels surface off roofs; mobile homes pushed off foundations or overturned; moving autos pushed off the roads; attached garages may be destroyed.
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.
F3 Severe tornado 158-206 mph Roof and some walls torn off well constructed houses; trains overturned; most trees in fores uprooted.
F4 Devastating tornado 207-260 mph Well-constructed houses leveled; structures with weak foundations blown off some distance; cars thrown and large missiles generated.
F5 Incredible tornado 261-318 mph Strong frame houses lifted off foundations and carried considerable distances to disintegrate; automobile sized missiles fly through the air in excess of 100 meters; trees debarked; steel re-inforced concrete structures badly damaged.
F6 Inconceivable tornado 319-379 mph These winds are very unlikely. The small area of damage they might produce would probably not be recognizable along with the mess produced by F4 and F5 wind that would surround the F6 winds. Missiles, such as cars and refrigerators would do serious secondary damage that could not be directly identified as F6 damage. If this level is ever acheived, evidence for it migh only be found in some manner of ground swirl pattern, for it may never be identifiable through engineering studies.

SAFETY

Protect your head.
Stay away from windows, doors, and outside walls.
In homes and small buildings: go to the basement, or to an interior area of the lowest level, if an underground shelter is not available. Closets, bathrooms and interior halls offer the most protection.
Get under something sturdy. In schools, nursing homes, hospitals, factories, and shopping centers, go to predesignated shelter areas.
In high-rise buildings: go to the interior small rooms or hallways on as low a floor as possible.
In mobile homes or vehicles: leave and take shelter in a substantial structure. If there is no nearby shelter, lie flat in the nearest ditch or ravine with your hands shielding your head.

THE FUJITA SCALE
F-Scale Number	Intensity Phrase	Wind Speed	Type of Damage Done
F0	Gale tornado	40-72 mph	Some damage to chimneys; breaks branches off trees; pushes over shallow-rooted trees; damages sign boards.
F1	Moderate tornado	73-112 mph	The lower limit is the beginning of hurricane wind speed; peels surface off roofs; mobile homes pushed off foundations or overturned; moving autos pushed off the roads; attached garages may be destroyed.
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.
F3	Severe tornado	158-206 mph	Roof and some walls torn off well constructed houses; trains overturned; most trees in fores uprooted.
F4	Devastating tornado	207-260 mph	Well-constructed houses leveled; structures with weak foundations blown off some distance; cars thrown and large missiles generated.
F5	Incredible tornado	261-318 mph	Strong frame houses lifted off foundations and carried considerable distances to disintegrate; automobile sized missiles fly through the air in excess of 100 meters; trees debarked; steel re-inforced concrete structures badly damaged.
F6	Inconceivable tornado	319-379 mph	These winds are very unlikely. The small area of damage they might produce would probably not be recognizable along with the mess produced by F4 and F5 wind that would surround the F6 winds. Missiles, such as cars and refrigerators would do serious secondary damage that could not be directly identified as F6 damage. If this level is ever acheived, evidence for it migh only be found in some manner of ground swirl pattern, for it may never be identifiable through engineering studies.