To understand just how wild the weather has been in the Midwest this month, consider Clark County, Wisconsin.
On Dec. 11, the rural western Wisconsin county dotted with picturesque farms and bountiful forestland, was blanketed with 7 to 8 inches of snow — fairly normal for this time of year. Four days later, on Dec. 15, the county was hit by three powerful EF-2 tornadoes — not even remotely close to normal and "crazy talk" for the middle of December, as one meteorologist described it.
It's not often that meteorologists and insurance claims representatives find themselves dealing with catastrophic severe storms in Wisconsin and the Midwest right before Christmas.
Yet, that's exactly what is taking place as weather researchers study the atmospheric conditions that were in place and insurers seek to help policyholders recover after violent storms rocked the Upper Midwest Dec. 15 and 16 on the heels of devastating tornadoes that pulverized parts of the Midwest and Mid-south Dec. 10 and 11.
First ever Dec. 15 tornado watch
In Wisconsin, Dec. 15 was the first time a tornado watch has ever been issued anywhere in the state during the month of December, according to the National Weather Service.
"With the storms down in Kentucky plus this (storms in Upper Midwest), it is definitely a rare kind of setup... especially in December," said Kevin Wagner, a weather service meteorologist in Sullivan. "It will definitely be looked at into the future for research."
In Wisconsin, the weather service says three EF-2 tornadoes, with winds estimated at 120 to 130 mph occurred on Dec. 15 in Clark County, which is about 50 miles east of Eau Claire.
Two other EF-0 tornadoes occurred Dec. 15 in western Wisconsin.
Tornadoes are rated based on the amount of damage they do. EF-2 tornadoes cause "considerable damage," and can tear roofs off houses, cause homes to shift off their foundations and destroy mobile homes.
Most tornadoes in Wisconsin are rated EF-0, with wind speeds of 65 to 85 mph.
"Tornadoes in Wisconsin are not unheard of, but not a tornado outbreak like that, let alone not EF-2s," said Alex Bukvich, director of operations for the Innovative Weather program, part of the atmospheric science department at the University of Wisconsin-Milwaukee.
Toss in that the twisters occurred in mid-December, and, "It was definitely irregular to see that kind of severe weather," Bukvich said.
In addition to record high temperatures, the ferocity of the storm system on Dec. 15 was noted by the weather service.
"The storm system was so powerful, it transported smoke from numerous large wildfires that ignited in western and central Kansas, all the way up into Wisconsin," according to a recap of the storms issued by the weather service office in Sullivan. "We had many reports of seeing haze from the smoke..."
45 confirmed tornadoes
At least 45 tornadoes have been preliminarily confirmed across the Plains and Midwest on Dec. 15, said Bill Bunting, chief of forecast operations at the weather service's Storm Prediction Center.
Bunting said at least 12 of the tornadoes, including the three in Clark County, were rated EF-2. Many of the thunderstorms also carried winds of up to 80 mph.
Five deaths were blamed on the weather.
Bunting said that normally in December, air from the Gulf of Mexico has cooled, and colder air is present in the Upper Midwest — factors that reduce the risk of severe thunderstorms and tornadoes. But this year, "we haven't had much of a winter," he said.
"So you had a very strong storm system with really somewhat unprecedented access to very warm, humid air that flows northward, and those are the ingredients that you look for for severe thunderstorms," Bunting said.
"The result was quite remarkable for December."
Insurers handling thousands of storm damage claims
The storms prompted West Bend Mutual Insurance to declare a December catastrophe for only the second time in at least 20 years, said Jim Schwalen, senior vice president, personal lines and marketing, at the company.
The insurer, located in its namesake community, West Bend, about 30 miles northwest of Milwaukee, was founded in 1894.
The only other December catastrophe in the past two decades was in 2007 "and involved winter weather which caused ice damming from excessive snowfall," Schwalen said.
So far, the company has received more than 1,000 claims resulting from storm and wind damage this month across Wisconsin, Iowa and Minnesota.
The claims range from trees having fallen on houses, to shingles blown off roofs to buildings "shifted off their foundation," Schwalen said.
As of Dec. 20, Madison-based American Family Insurance and its subsidiaries had received more than 9,000 storm damage claims "from the two (December) storm systems across the western, midwestern and southern states," said Erin Johansen, a spokeswoman for the insurer, in an email.
American Family has received claims from customers in Wisconsin, Kentucky, Iowa, Kansas, Nebraska, Colorado, Illinois, Minnesota and Missouri.
The company's insurance brands include CONNECT, powered by American Family Insurance, The General, Homesite and Main Street America Insurance.
Merrill-based Church Mutual Insurance Co. is among the nation's largest insurers of religious organizations and also provides insurance for nonprofit and human services organizations, public and private K-12 schools, colleges and universities, senior living facilities, camps and conference centers throughout the United States.
The company is still tallying the number of claims it has received as a result of the two December storm systems, said Dawn Bernatz, a company spokeswoman.
"Right now, our team is working hard to support our customers and get them operational as quickly as possible," Bernatz said in an email. "Our customers often are essential to their communities and provide support during crisis times, so we focus on helping them as fast as we can."
The weather service has deemed many aspects of the two storm systems "historic."
Rich Poirier, CEO of Church Mutual, would agree.
"I have never seen this type of storm activity, of this intensity, at this time of year," Poirier said. He's been in the insurance business for 32 years.
Among other insurers, State Farm has received more than 10,000 claims from the Dec. 15-16 storm system, primarily home and building damage, said Heather Paul, a spokeswoman for the Bloomington, Illinois-based insurer.
Of those claims, 1,000 are from Wisconsin policyholders, she said.
For the storm system that resulted in the devastating tornados in Kentucky, Tennessee, and surrounding states, State Farm has received more than 9,000 claims, Paul said.
Dec. 15 storm has been declared a derecho
The line of storms that swept across the Upper Midwest on Dec. 15 has been declared a "serial derecho" — the first on record in December, officials with the Weather Service said.
A derecho is often described as an inland hurricane. But, it has no eye and its winds come across in a line. The similarity is in the damage, which is likely to spread over a wide area, unlike a tornado where the damage is more spotty.
The weather service said a wind damage swath extending more than 240 miles with wind gusts of at least 58 mph along most of its length can be classified as a derecho.
A derecho was also declared in August 2020 when storms packing 100 mph winds lasted several hours and caused damage from eastern Nebraska, across Iowa and into parts of Wisconsin and Illinois.
There was a difference: The August 2020 storm was a "progressive derecho," while the one in December was a serial derecho.
The weather service said a progressive derecho is fueled by a hot and moist environment with relatively strong winds aloft.
Serial derechos are produced by storms with strong winds that bow outward, the service said. They sweep across an area both long and wide, driven by the presence of very strong winds in the atmosphere.
Derechos are more likely to occur from May through August, particularly during periods of high heat — making the December derecho so uncommon.
"It's definitely something we don't see very often," Wagner said.
The Associated Press contributed to this report
December 2021: Wild weather in Wisconsin
The only tornado watch ever issued in Wisconsin during the month of December was issued during the early evening on Dec. 15.
Areas around Neillsville, in Clark County, tallied 7 to 8 inches of snow on Dec. 11. Four days later, during the nighttime hours of Dec. 15, the area was hit by three EF-2 tornadoes.
Green Bay's high temperature of 65 degrees on Dec. 16 was the highest temperature ever recorded there in the month of December.
A peak wind gust of 76 mph was reported at 2:49 a.m. on Dec. 16 at the Rhinelander airport. That's 18 mph over the 58 mph threshold for issuing a severe weather warning. A high wind warning was in place for the entire state at the time and residents were being encouraged to seek shelter as if severe thunderstorms were occurring.
La Crosse Regional Airport recorded a wind gust of 68 mph on Dec. 15, the second-highest wind gust ever recorded at the airport. The highest gust ever at the La Crosse airport was 78 mph on March 30, 1982.