|Funnel cloud or tornado?|
Q: Is there a difference between a funnel cloud and a tornado?
A: It’s all in the timing, says Brent McRoberts of Texas A&M University. A funnel cloud is a powerful twisting mass of air stretching down from a thunderstorm, but it has not yet touched the ground. “Once it makes contact with the ground, it’s then officially called a tornado,” McRoberts explains. “That means that a funnel cloud has become a tornado. A funnel cloud doesn’t do much damage up in the air, but once it makes contact with the ground, that’s when trouble starts. If a funnel cloud is spotted, it should be treated like it is a tornado because the situation can change quickly and become a life-threatening event.”
Q: Once it does touch the ground, how fast can it travel?
A: Most tornadoes travel fairly slowly, at about 20 miles per hour or so, McRoberts says. “But some have been clocked at 60 to 70 miles per hour. You have to realize that the winds inside the tornado are much faster than the rate at which the storm moves on the ground. Winds inside a tornado can reach 300 miles per hour, which is why they cause so much destruction and death. In any year, there are about 100,000 thunderstorms in the United States and these produce about 1,000 tornadoes every year. Some travel just a few hundred feet, while others have been known to travel more than 100 miles on the ground. Studies show that the average tornado will travel a little over 3 miles on the ground.”