In southeastern Minnesota, Olmsted County Sheriff’s Lt. Lee Rossman said a 65-year-old man was killed Wednesday night when a 40-foot tree blew onto him outside his home. In southwestern Kansas, blinding dust kicked up by the storms Wednesday led to two separate crashes that killed three people, Kansas Highway Patrol trooper Mike Racy said. And in eastern Iowa, a semitrailer was struck by high winds and rolled onto its side Wednesday evening, killing the driver, the Iowa State Patrol confirmed.

The storm shifted north of the Great Lakes into Canada on Thursday, with high winds, snow and hazardous conditions continuing in the upper Great Lakes region, the National Weather Service said. More than 190,000 homes and businesses remained without electricity Thursday afternoon in Michigan, Wisconsin, Iowa and Kansas, according to poweroutage.us, which tracks utility reports.

At least two tornadoes were confirmed in southern Minnesota on Wednesday, the state’s first twisters on record in December. The small community of Hartland, Minnesota, might have been the hardest hit, with a reported 35 to 40 homes sustaining minor damage and a few businesses severely damaged, Freeborn County Emergency Management Director Rich Hall said. Winds reached at least 110 mph in Hartland, the National Weather Service said.

Losses also included livestock. Dozens of cows were electrocuted at a dairy farm after a power pole landed on a milking barn in Newaygo County, in western Michigan. Tim Butler said his workers at the dairy survived the event, but at least 70 cows died. Dozens survived, but many were “hurt bad,” Butler said.

The destructive weather system developed amid unprecedented warmth for December in the Plains and northern states. That included temperatures that rose to 70 degrees Fahrenheit (21 degrees Celsius) across southwestern Wisconsin on Wednesday evening. The Weather Company historian Chris Burt compared the heat to that of a “warm July evening.”

“I can say with some confidence that this event (the heat and tornadoes) is among the most (if not THE most) anomalous weather event ever on record for the Upper Midwest,” Burt wrote in a Facebook post.

The winds knocked down trees, tree limbs and nearly 150 power lines in northern and western Michigan’s Lower Peninsula. In the western Michigan village of Fruitport, high winds peeled back a portion of Edgewood Elementary School’s roof, leading officials to close all district schools Thursday.

There were more than 20 tornado reports Wednesday in the Plains states, scattered mostly through eastern Nebraska and Iowa, based on preliminary reports to the Storm Prediction Center. The storm system led to the most reports of hurricane-force wind gusts — 75 mph (120 kph) or higher — on any day in the U.S. since 2004, the center said.

“To have this number of damaging wind storms at one time would be unusual anytime of year,” said Brian Barjenbruch, a meteorologist with the National Weather Service in Valley, Nebraska. “But to have this happen in December is really abnormal.”

The governors of Kansas and Iowa declared states of emergency.

The system came on the heels of devastating tornadoes last weekend that cut a path through states including Arkansas, Missouri, Tennessee, Illinois and Kentucky, killing more than 85 people.

On Wednesday, there were at least 59 reports of hurricane-force wind gusts regionwide, which exceeded the 53 recorded on Aug. 10, 2020, when a rare derecho wind storm struck Iowa, the Storm Prediction Center said. The destruction on Wednesday, however, was far less severe than from last year’s derecho, which caused billions of dollars of damage.

The winds also whipped up dust that reduced visibility to zero in parts of Kansas and caused at least four semitrailers to blow over, leading officials to temporarily close much of Interstate 70, as well as all state highways in nine northwestern Kansas counties.

Kansas deployed helicopters and other firefighting equipment to help smother at least a dozen wind-fueled wildfires in western and central counties, officials said Thursday.

That dust and smoke was carried north by the storm and concentrated over parts of Kansas, Nebraska and Iowa, causing a dramatic drop in air quality in those areas late Wednesday. That spawned a glut of calls to already-taxed emergency dispatchers from people reporting the smell of smoke.

The system blew into the Plains from Colorado, sending gale-force winds across a swath from New Mexico to Minnesota, Wisconsin and upper Michigan. The weather service recorded a gust of 107 mph (172 kph) Wednesday morning at Lamar, Colorado, and gusts of 100 mph in Russell, Kansas.

Scientists say extreme weather events and warmer temperatures are more likely to occur with human-caused climate change. However, scientifically attributing a storm system to global warming requires specific analysis and computer simulations that take time, haven’t been done and sometimes show no clear connection.

“I think we also need to stop asking the question of whether or not this event was caused by climate change,” said Northern Illinois University meteorology professor Victor Gensini. “We need to be asking, `To what extent did climate change play a role and how likely was this event to occur in the absence of climate change?’”

The unusually warm temperatures on Wednesday were due in part to record high ocean temperatures in the Gulf of Mexico, which wouldn’t have happened without global warming, said Jeff Masters, a Yale Climate Connections meteorologist who cofounded Weather Underground.