1. Tornadoes

2. What is a tornado?
A tornado is a violent whirling wind that moves across the ground in a narrow path.

3. How are Tornadoes formed?
Late in the day, when earth’s surface is very warm, convection (The flow of heat through a material, causing hot parts to rise and cooler parts to sink.) can get very strong. This can lead to a tornado.

4. A tornado is a sort of a runaway convection cell.
A convection cell is a circular pattern of air rising, air sinking and wind.

5. Tornado Happenings
1.When the updraft in a convection cell is really strong, the air rushes in from all sides at high speeds.

6. 2. Air curves into a spin. This lowers the pressure even more
2. Air curves into a spin. This lowers the pressure even more. Air rushes in even faster, and the pressure gets even lower, and so on.
Like a skater who pulls her arms in close to her sides. The tornado spins faster and faster.

7. 3. As the tornado gets stronger, a funnel forms that can destroy anything in it’s path. The center of the tornado can reach speeds of 500 kilometers per hour (about 300 miles per hour) or more.

8. Where Do Tornadoes Happen?
Tornadoes happen where dry, cold air masses mix with warm, moist air masses.
More tornadoes occur in the United States than in any other country, especially in the area known as TORNADO ALLEY.

9. A Famous Tornado
Grand Island, Nebraska
June 3, 1980

10. On June 3, 1980, a series of tornadoes devastated the city of Grand Island, Nebraska. Seven tornadoes hit within a three hour period. The storm did massive damage and closed the city down for three days.

11. What is a Hurricanes
A hurricane can best be described as a huge tropical storm with winds up to 200 mph!
Storm usually doesn’t last for more than 7-10 days.
As it moves inland it continues to move across the land but it begins to weaken

12. Intertropical Convergence Zone
The ITCZ is an area of low pressure located roughly 5 degrees North and South of the Equator. It is a place where air converges, rises, and condenses (forming clouds). It is the rainiest place on Earth!

13. So What Does a Hurricane Need in Order to Develop?
So a hurricane needs warm water, time to grow, and favorable upper level winds in the troposphere. If the winds are too strong, they will blow the hurricane apart – we call that wind shear!

14. The End