Third Day of Storms Forecast After Oklahoma Devastation

A swath of the Midwest that’s home to 63.9 million people faced a third day of tornadoes, powerful thunderstorms and damaging hail from the same system that spawned yesterday’s deadly Oklahoma twister.

An area from Dallas to Little Rock, Arkansas, has the greatest chance of severe weather, while a portion of the central U.S. from Michigan to Texas is at risk, according to the U.S. Storm Prediction Center.

“It is unlikely that you will see something as extreme as what was witnessed yesterday,” said Tom Downs, a forensic meteorologist at Weather 2000 Inc. in New York. “I think it appears the most severe events are over for now.”

At least 24 people were confirmed dead after a massive tornado swept through Moore, Oklahoma, a suburb of Oklahoma City, flattening homes and schools, downing power lines and uprooting trees. The twister was one of 14 reported from Colorado to Kansas yesterday.

Today’s “real areas of concern are Arkansas, northern Louisiana and northeastern Texas, where you could have the most damaging storms,” said Christopher Vaccaro, spokesman for the National Weather Service in Silver Spring, Maryland. The Moore storm “is certainly on the high end of the scale” in terms of destructiveness, he said.

Oklahoma Strikes

Oklahoma City has been struck by tornadoes more times than any other place in the U.S., according to government data. Yesterday’s storm came the day after two people were killed and 39 injured in separate storms in the state. At least 30 tornadoes were reported on May 19 from Illinois to Oklahoma.

The exact strength of yesterday’s storm won’t be known until a survey team inspects the damage in the coming days, said John Pike, a spokesman with the weather service in Norman, Oklahoma, about 10 miles south of Moore.

Preliminary indications were that it was at least an EF-4 tornado on the Enhanced Fujita Scale, said Ryan Barnes, a weather service meteorologist. That’s the second-most-powerful classification on the six-step rankings and means the cyclone had wind gusts of 166 to 200 miles (267 to 322 kilometers) per hour for three seconds.

Ranking Tornadoes

Classification is based on damage, not actual wind measurements. Tornadoes can last from several seconds to more than an hour, with the most storms breaking up within 10 minutes, according to the storm center. The swath of devastation shown on television is consistent with an EF-5 tornado, the most powerful kind, with winds of at least 200 miles per hour, said Mark Hoekzema, chief meteorologist for Earth Networks in Germantown, Maryland.

“From everything that I have seen it is undoubtedly an EF-5 and it is one of the worst ones I have seen,” Hoekzema said by telephone. “This appears to have been very wide and to have gone through a substantially populated area.”

There were only 58 EF-5 tornadoes recorded in the U.S. between 1950 and 2011, according to the storm center. About 1,300 tornadoes hit the country every year.

Severe thunderstorms killed 118 people in the U.S. last year and caused an estimated $27.7 billion in economic losses, second only to hurricanes and tropical storms among natural disasters, according to the Insurance Information Institute of New York.

The tornado season this year got off to a slow start because the U.S. spring was cooler than normal, Hoekzema said. Conditions in the last week have changed, making storms more likely to form, he said.

As of May 19, 304 tornadoes had been reported, less than the 714 annual average for that date, according to the storm center.

“It has been eerily quiet,” Downs said. “We have had to wait three months and everything is kind of overdue.”

Before it's here, it's on the Bloomberg Terminal.