The Outbreak of Powerful Tornadoes

The tornado that plowed a wide swath of death and destruction through Joplin, Mo., on Sunday unleashed winds of up to 198 miles per hour, federal forecasters said yesterday.

The National Oceanic and Atmospheric Administration's preliminary analysis ranks the twister as an F4, the second-highest rating on the five-point scale used to classify tornadoes.

Agency officials said the Joplin storm, at times three-quarters of a mile wide, was the deadliest single tornado to hit the United States since 1953. At least 116 people died and 500 were injured by the storm. The numbers are expected to climb as aid workers comb through the wreckage left behind.

"This is the ninth-deadliest tornado year on record so far," said Jack Hayes, director of NOAA's National Weather Service. "More than 450 people have been killed.... With so many fatalities this year, I think we have to ask ourselves the tough questions now. Why is this happening?"…

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