Average tornadoes move at less than 35 miles per hour and lastjust a few minutes, but yesterday a two-mile wide EF4 tornadopacking 166 to 200 mph winds ripped through the suburbs of OklahomaCity for 40 minutes.

It left 24 people dead, but the toll is expected to rise asbodies are examined in the Oklahoma Medical Examiner's Office. 240more have been injured, including at least 60 children, and dozensare still missing.

“Insurance claims adjusters have already begun helpingpolicyholders and will be within the disaster zone itself as soonas permitted while some insurers have already deployed their mobileclaims units to the vicinity,” says Jim Whittle, chief claimscounsel for the American Insurance Association (AIA).

The storm was part of a system that is still putting 53 million people at risk innorth-central Texas, southeastern Oklahoma, and parts of Arkansasand Louisiana as it develops on Tuesday.

Many of the juvenile deaths yesterday occurred when the tornadodirectly hit and demolished the Plaza Towers Elementary School,trapping those huddling inside and drowning seven students in thebasement.

Another elementary school, a hospital, and an as-yet-unknownnumber of homes have been razed.

The National Guard and federal aid was deployed to Moore, thehardest-hit suburb south of the state capital, and 16 othercounties after President Obama declared the disaster a nationalemergency. Responders are still at work in the area.

“It is important for homeowners and business owners to know thatstandard homeowners and business insurance policies cover winddamage to the structure of insured buildings, and their contents,if caused by either tornadoes or thunderstorms,” says LorettaWorters, spokeswoman for the Insurance Information Institute(I.I.I.).

“When purchasing coverage for the structure of your home, it isimportant to buy enough to rebuild your home […] Most companiesprovide coverage for 50 percent to 70 percent of the amount ofinsurance you have on the structure of your home,” shesays.

State Farm media contact Jim Camoriano says responders are notyet letting claims people into the hardest-hit areas as the searchfor survivors goes on.

“We did get a call from an agent who had a policyholder whosehouse was blown off its foundation and destroyed,” Camoriano says.“The family's son or daughter was walking through rubble and sawpiece of paper sticking out; it was their homeowner's policy.That's how she knew where to call for help, and this morning theagent can give her a $5,000 check to help with lodging andadditional living expenses (ALE).”

Eyewitness accounts from local-news sources say that unlikeother tornadoes, which seem to pick and choose homes to destroy andthose to leave alone, yesterday's twister left little except rubblein Moore, a town of about 55,000.

More than 40,000 people were reported still without power thismorning, with more than half of those in Moore.

“The challenge has been working while the power is down,” saysNicole Alley, spokeswoman for USAA, which has 120 adjusterscurrently on the ground. “We have received approximately 350 autoand homeowners claims from the tornado, but we anticipate morecalls as cell towers become more available.”

Moore was ravaged by an EF5 tornado in May 1999, the strongesttornado in recorded history and one of the costliest. With windspeeds of about 318 mph, it killed 36 people near Oklahoma City andcaused $1 billion in losses.

“I can tell you that tornadoes this spring have been some of the costliest—and deadliest—inU.S. history,” says Worters.

I.I.I. data says that the Tuscaloosa and Joplin tornadoes in2011 cost $7.5 billion and $7.0 billion in insured damages,respectively, and that severe convective storms from 2008 to 2010have caused about $30 billion.

Although average thunderstorm losses have increased sevenfoldsince 1980, The National Weather Service counted 70 tornado-relateddeaths in the U.S. in 2012, and until just last week, 2013 wasconsidered a mild year for convective storms.