TornadoesTornadoes

What is a Tornado?What is a Tornado? A tornado is a A tornado is a

violent violent rotating rotating column of air column of air extending extending from a from a thunderstorm thunderstorm to the ground.to the ground.

How do Tornadoes How do Tornadoes FormForm

Warm moist air comes North from Warm moist air comes North from the Gulf of Mexico and collides with the Gulf of Mexico and collides with Cool Dry air from Canada.Cool Dry air from Canada. There is a large difference in There is a large difference in

temperature and moisture between temperature and moisture between the masses.the masses.

Meeting masses create instability in Meeting masses create instability in the atmosphere.the atmosphere.

Rising air within the updraft tilts the Rising air within the updraft tilts the rotating air from horizontal to verticalrotating air from horizontal to vertical

A larger pressure difference will indicate A larger pressure difference will indicate faster speeds and more energy of a tornado.faster speeds and more energy of a tornado.

An average tornado will be 400 to An average tornado will be 400 to 500 feet wide and travel four or 500 feet wide and travel four or five miles on the ground, lasting five miles on the ground, lasting only a few minutes only a few minutes

When are tornadoes likely When are tornadoes likely to occur?to occur?

3pm – 9pm are likely times of day3pm – 9pm are likely times of day Surface heating creates maximum Surface heating creates maximum

number of convection currents in the number of convection currents in the atmosphereatmosphere

March-May for southern statesMarch-May for southern states Summer months for northern statesSummer months for northern states

Warm air masses are more likely from Warm air masses are more likely from the Gulf of Mexico during this time.the Gulf of Mexico during this time.

Where are Tornadoes Where are Tornadoes Likely to form?Likely to form?

Tornado alley is in an area of the Tornado alley is in an area of the great plains, East of the Rocky great plains, East of the Rocky mountains.mountains.

(cP air masses mix with mT air (cP air masses mix with mT air masses)masses)

Fujita Scale of Tornado Fujita Scale of Tornado IntensityIntensity

Dangers of TornadoesDangers of Tornadoes Tornadoes may have a diameter of Tornadoes may have a diameter of

2-3 km.2-3 km. Wind speeds range from 40-318 Wind speeds range from 40-318

mphmph Hail stones can be generatedHail stones can be generated

Tornado DamageTornado Damage

Spotting a TornadoSpotting a Tornado There is typically There is typically

a distinctive hook a distinctive hook found on Doppler found on Doppler radar.radar.

Warning systemsWarning systems Tornado Watch:Tornado Watch:

Issued to alert people to the Issued to alert people to the possibility of tornado development in possibility of tornado development in your area your area

Tornado Warning:Tornado Warning: Issued when a tornado has actually Issued when a tornado has actually

been sighted or is indicated by radar.been sighted or is indicated by radar.