The destructive storm system that pummeled the Midwest on Nov.17 with lightning, hail, high winds and heavy rain may carry aprice tag of up to $1 billion, according to Risk ManagementSolutions. Additionally, the storm could rank as the most expensiveof the top five catastrophes of its kind to have occurred inNovember since 1950.

State Farm spokeswoman Holly Anderson said the insurer hadreceived 1,800 homeowners claims in Illinois, 1,200 in Idaho and600 in Michigan in the three days following the disaster. The StormPrediction Center (SPC) registered 67 tornado touchdowns in severalstates, as well as straight-line winds of more than 85 mph andbaseball-sized hail. Six people were killed, including at leastfive in Illinois.

“This is very unusual for this time of year,” Jeff Ormond,Allstate spokesperson for the insurer's regional office overseeingOhio, Michigan and Indiana, tells NU. “Usually the region would see[such] weather in the warmer months of May through September. Wedid have tornadoes in Henryville, Ind. and Dexter, Mich. in March2012, which was very unusual at that time, too.”

According to Aon Benfield, Nov. 17 provided “highly conducive”atmospheric conditions for explosive thunderstorm development.Illinois, Indiana and Kentucky bore the brunt of the storm'sdamage, which the SPC says at its peak threatened more than 53million people in 10 states.

Illinois saw the worst of it. National Weather Servicemeteorologists recorded an EF-4 twister in New Minden, Ill. thatcompletely wiped a farmhouse off its foundation, killing an elderlyman and his sister. It was one of only 20 tornadoes of similarstrength to occur during the month of November since the middle ofthe last century.

Two other tornadoes, an EF-2 that swept across Grundy and Willcounties, and a deadly twister in the Peoria region, claimed homesand an apartment complex. Other touchdowns laid waste to countlessmobile homes.

At least 12 counties in Indiana reported tornado damage, withstates of emergency declared in Howard County, home to the towns ofKokomo, Russiaville and Greentown. Severe damage was also reportedin Lafayette, Washington and Lebanon cities. One tornado inLogansport caused gas leaks that prompted several complexes to beevacuated.

Overall, the event was a turning point for an otherwise calmyear for convective storms and tornadoes. According to theInsurance Information Institute, only 818 tornadoes had beenconfirmed this year, the lowest annual count since 1988.

Now, however, there have been five severe-weather outbreaks inthe U.S., the third-highest total in the country's history behind2011 and 2012. The most expensive and deadliest single tornadooutbreak occurred in May and devastated Moore, Okla., which costabout $562 million in payouts.

U.S. thunderstorms cost $14.9 billion insured losses in 2012,reports Munich Re. The U.S. experiences more tornadoes than anyother country worldwide.