Tornadoes

What is a Tornado? A tornado is a violent rotating column of air extending from a thunderstorm to the ground. A tornado is a violent rotating column of air extending from a thunderstorm to the ground.

How do Tornadoes Form Warm moist air comes North from the Gulf of Mexico and collides with Cool Dry air from Canada. Warm moist air comes North from the Gulf of Mexico and collides with Cool Dry air from Canada. There is a large difference in temperature and moisture between the masses. There is a large difference in temperature and moisture between the masses. Meeting masses create instability in the atmosphere. Meeting masses create instability in the atmosphere.

Rising air within the updraft tilts the rotating air from horizontal to vertical Rising air within the updraft tilts the rotating air from horizontal to vertical A larger pressure difference will indicate faster speeds and more energy of a tornado. A larger pressure difference will indicate faster speeds and more energy of a tornado.

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

When are tornadoes likely to occur? 3pm – 9pm are likely times of day 3pm – 9pm are likely times of day Surface heating creates maximum number of convection currents in the atmosphere Surface heating creates maximum number of convection currents in the atmosphere March-May for southern states March-May for southern states Summer months for northern states Summer months for northern states Warm air masses are more likely from the Gulf of Mexico during this time. Warm air masses are more likely from the Gulf of Mexico during this time.

Where are Tornadoes Likely to form?

Tornado alley is in an area of the great plains, East of the Rocky mountains. Tornado alley is in an area of the great plains, East of the Rocky mountains. (cP air masses mix with mT air masses)

Fujita Scale of Tornado Intensity

Dangers of Tornadoes Tornadoes may have a diameter of 2-3 km. Tornadoes may have a diameter of 2-3 km. Wind speeds range from mph Wind speeds range from mph Hail stones can be generated Hail stones can be generated

Tornado Damage

Spotting a Tornado There is typically a distinctive hook found on Doppler radar. There is typically a distinctive hook found on Doppler radar.

Warning systems Tornado Watch: Tornado Watch: Issued to alert people to the possibility of tornado development in your area Issued to alert people to the possibility of tornado development in your area Tornado Warning: Tornado Warning: Issued when a tornado has actually been sighted or is indicated by radar. Issued when a tornado has actually been sighted or is indicated by radar.