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

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

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

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

“When purchasing coverage for the structure of your home, it is important to buy enough to rebuild your home […] Most companies provide coverage for 50 percent to 70 percent of the amount of insurance you have on the structure of your home,” she says.

State Farm media contact Jim Camoriano says responders are not yet letting claims people into the hardest-hit areas as the search for survivors goes on.

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

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

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

“The challenge has been working while the power is down,” says Nicole Alley, spokeswoman for USAA, which has 120 adjusters currently on the ground. “We have received approximately 350 auto and homeowners claims from the tornado, but we anticipate more calls as cell towers become more available.”

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

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

I.I.I. data says that the Tuscaloosa and Joplin tornadoes in 2011 cost $7.5 billion and $7.0 billion in insured damages, respectively, and that severe convective storms from 2008 to 2010 have caused about $30 billion.

Although average thunderstorm losses have increased sevenfold since 1980, The National Weather Service counted 70 tornado-related deaths in the U.S. in 2012, and until just last week, 2013 was considered a mild year for convective storms.