1. What is a severe thunderstorm?
A severe thunderstorm produces large hail 1 inch in diameter or larger, damaging winds of 58 mph or greater, and/or a tornado.
2. What is a tornado?
It is a column of violently rotating winds extending down from a thunderstorm cloud and touching the surface of the earth.
3. What is the difference between a tornado and a funnel cloud?
A funnel cloud is also a column of violently rotating winds extending down from a thunderstorm; however, it does not touch the earth.
4. How many tornadoes usually occur in Michigan every year?
An average of 16 tornadoes occurs in Michigan each year. From 1950 to 2008, 242 persons have been killed due to tornadoes. During this same time, Michigan has experienced 920 tornadoes.
5. When do tornadoes generally occur?
Most tornadoes occur during the months of May, June, July and August in the late afternoon and evening hours. However, tornadoes can occur anytime of the day or night in almost any month during the year.
6. How fast do tornadoes travel?
Tornadoes generally travel from the southwest and at an average speed of 30 miles per hour. However, some tornadoes have very erratic paths, with speeds approaching 70 mph.
7. How far do tornadoes travel once they touch the ground?
The average Michigan tornado is on the ground for less than 10 minutes and travels a distance of about 5 miles. However, they do not always follow the norm, and have been known to stay on the ground for more than an hour and travel more than 100 miles.
8. What is a tornado watch? What is a severe thunderstorm watch?
A tornado/severe thunderstorm watch is issued whenever conditions exist for severe weather to develop. Watches are usually for large areas about two-thirds the size of Lower Michigan and are usually two-to-six hours long. Watches give you time to plan and prepare.
9. What is a tornado warning? What is a severe thunderstorm warning?
The local National Weather Service (NWS) office issues a tornado warning whenever NWS Doppler Radar indicates a thunderstorm capable of producing a tornado or when a tornado has been sighted by a credible source. A severe thunderstorm warning is issued whenever a severe thunderstorm is observed or NWS Doppler Radar indicates a thunderstorm capable of producing damaging winds or large hail.
Warnings are issued for even smaller areas, such as parts of counties. “Storm-based” warnings began on October 1, 2007. The NWS issues warnings for the threatened area in a shape of a polygon. The “polygon” warnings will only include sections of a county or group of counties, and are usually 30 to 90 minutes in length. You must act immediately when you first hear the warning. If severe weather is reported near you, seek shelter immediately. If not, keep a constant lookout for severe weather and stay near a shelter.
10. How do I find out about a warning if my electricity is already out?
NOAA Weather Radio All Hazards with battery back-up capability is your best source to receive the warning. In some areas, civil emergency sirens may be your first official warning. In addition, if your television or radio has battery back-up capability you may receive NOAA’s National Weather Service warnings from local media.