TornadoesTornadoes

20102010

TornadoesTornadoes

Rapidly rotating, Rapidly rotating, funnel shaped cloud.funnel shaped cloud.

Most locally Most locally destructive of all destructive of all storms.storms.

Usually touch the Usually touch the ground for only a ground for only a few minutes.few minutes.

Wind speeds can be Wind speeds can be over 200mph!over 200mph!

Tornado FormationTornado Formation

Develop in Develop in thunderstorms.thunderstorms.

If the rising updraft If the rising updraft in a thunderstorm in a thunderstorm changes direction, it changes direction, it can start to rotate.can start to rotate.

As this rotation As this rotation tightens, it gets tightens, it gets stronger but stronger but narrower.narrower.

Air Rotates Because of Air Rotates Because of Wind ShearWind Shear..

How the column of air How the column of air begins to rotate is not begins to rotate is not completely understood completely understood by scientists.by scientists.

Rotation appears to Rotation appears to happen when winds at happen when winds at two different altitudes two different altitudes blow at two different blow at two different speeds creating wind speeds creating wind shear.shear.

This causes a This causes a horizontal rotationhorizontal rotation

Faster Spin Makes a Funnel Faster Spin Makes a Funnel CloudCloud

If this column gets If this column gets caught in a supercell caught in a supercell updraft, the updraft updraft, the updraft tightens the spin tightens the spin and it speeds upand it speeds up

(much like a skater's (much like a skater's spins faster when spins faster when arms are pulled arms are pulled close to the body.)close to the body.)

A funnel cloud is A funnel cloud is created. created.

The Funnel Rotates and The Funnel Rotates and Touches DownTouches Down

The rain and hail in The rain and hail in the thunderstorm the thunderstorm cause the funnel to cause the funnel to touch down touch down creating a tornado.creating a tornado.

Tornado DamageTornado Damage Tornadoes are Tornadoes are

usually less than a usually less than a 100 yards wide.100 yards wide.

The damage they The damage they inflict is severe but inflict is severe but very localized.very localized.

Fujita Wind Damage ScaleFujita Wind Damage Scale This scale uses the This scale uses the

damage to damage to estimate the wind estimate the wind speed.speed.

The more severe, The more severe, the less common.the less common.

F-5’s are the F-5’s are the strongest, most strongest, most damaging damaging tornadoes.tornadoes.

Tornado SafetyTornado Safety Tornado Watch: Tornado Watch:

conditions are conditions are favorable for favorable for tornadoes.tornadoes.

Tornado Warning: Tornado Warning: Tornado has been Tornado has been sighted. Take cover sighted. Take cover if it is in your area.if it is in your area.

Basements are the Basements are the best place if there is best place if there is a tornado. a tornado.

Tornado AlleyTornado Alley The area over which The area over which

tornadoes occur most tornadoes occur most often in North America often in North America is called Tornado is called Tornado Alley. Alley.

It covers the Great It covers the Great Plains which is Plains which is between the Rocky between the Rocky Mountains and the Mountains and the Appalachian Appalachian Mountains. It includes Mountains. It includes all or half of the 13 all or half of the 13 mid-west states. mid-west states.

http://www.eo.ucar.edu/kids/dangerwx/tornado3.htm