Name _________________________________________ Date ___________
1. Where do the most tornadoes occur in the USA?
______________________________________________________________
2. What do you need for a tornado to form?
______________________________________________________________
______________________________________________________________
3. Which is the tornado capital of the world? Why?
_____________________________________________________________
4. What is the swirling mass of air in a tornado?
_____________________________________________________________
_____________________________________________________________
5. What is the average wind speed in a tornado?
____________________________________________________________
6. What actions should people take to protect themselves during a tornado?
____________________________________________________________
____________________________________________________________
____________________________________________________________
Answers
1. In central USA, nicknamed Tornado Alley.
2. A big thunderstorm; winds blowing from opposite directions; and a strong updraft. Strong updrafts surge up through storm clouds causing the cloud tops to bubble up and subside. A tornado can form when the air in these updrafts begins to rotate as opposing winds cause the storm to start spinning.
3. The USA, with more than 700 per year. The U.S. has this many tornadoes because of west winds. Winds from the west are forced to stream over the Rocky Mountains. On the other side these winds encounter the low, warm, moist winds from the Gulf of Mexico. These two air masses collide over the central USA and provide the possibility for tornado development. That's why Kansas had more than 1200 tornadoes from 1953 to 1980 while Alaska only had one.
4. The whirling mass of air and cloud is called a vortex and the spinning column of air within the vortex is called a mesocyclone. The air pressure in the center of the vortex drops as more air is sucked into it, although at the present time scientists do not know just how low the air pressure can get within the center of the vortex.
5. Wind speeds within a tornado may reach 600 miles per hour, and objects picked up by a tornado hurtle around it at the same speed.
6. Move to a pre-designated shelter such as a basement in a home or building. If an underground shelter is not available, move to an interior room or hallway on the lowest floor and get under a sturdy piece of furniture. Stay away from windows; get out of cars -- do not try to outrace a tornado. If you're caught outside, lie flat in a nearby ditch or depression.