readers' questions on tornadoes

Q. What's the widest tornado on record?

A. The Hallam, Neb., tornado in May 2004. It was measured at 2 1/2 miles wide.

Q. What tornado traveled the longest distance?

A. The Tri-State tornado of March 18, 1925, was on the ground for 3 1/2 hours, covering 219 miles from northwest of Ellington, Mo., to northeast of Princeton, Ind.

Q. What is the largest or tallest building a tornado has ever destroyed?

A. This statistic is not officially kept, but weather officials cited the Parsons Manufacturing Plant in Parsons in 2004 and the Hesston Concrete plant in 1990. The 37-story Bank One skyscraper in Fort Worth was so badly damaged after being hit by a tornado in 2000 that it was set to be razed, but developers eventually refurbished it and converted it into apartments.

Q. Why do tornadoes seem to hit trailer courts?

A. Because the death toll in trailer parks from tornadoes is higher than in more sturdily built homes, those incidents garner greater media attention — thus making it seem like tornadoes target trailer parks. And trailer parks are far more numerous than they were 60 years ago, so there are more of them that can be hit. But there is no meteorological explanation for why tornadoes hit trailer courts. The courts simply happen to be in the tornado's path.

Q. If you can have hurricane winds during a blizzard, can you have a tornado as well?

A. No. Tornadoes are spawned by thunderstorms that feed off warm, moist air — which isn't present during a blizzard.

Q. What's the fastest speed ever recorded for a tornado?

A. That's another statistic I have found no detailed records for, but tornado speeds are determined by the speed of the storm system that spawns them. Speeds of 60 to 70 miles an hour are not unusual — particularly in the early spring, when the jet stream is strong. That's why people are discouraged from trying to outrun tornadoes in their vehicles. The Tri-State Tornado was clocked at more than 70 miles an hour during its existence. Mike Smith of WeatherData Inc. said the fastest tornado he has heard of was clocked at 83 mph.

Q. What's the fastest internal wind speed for a tornado?

A. The tornado that struck Moore, Okla., on May 3, 1999, had wind speeds clocked at 302 mph by a Doppler on Wheels. Other recent tornadoes may have been just as strong, meteorologists say, though there wasn't a DOW close enough to clock them. After studying damage caused by the Goessel tornado on March 13, 1990, Theodore Fujita estimated its wind speeds at more than 300 mph. Meteorologists say the Greensburg and Trousdale tornadoes on May 4, 2007, may well have been just as strong.

Q. Are there any states in the union that have never recorded a tornado?

A. No.

Q. Does the placement of lakes direct where tornadoes travel? It always seems like they veer a different direction when they get near a body of water.

A. Lakes have no bearing on a tornado's path.

Q. There was an old Indian belief that tornadoes will not cross rivers. Is that true?

A. No. The Hesston tornado crossed the Arkansas River in 1990, and the Andover tornado crossed the Arkansas in 1991. Those are just two of countless examples reflecting the fallacy of that myth.