Communities in at least five states scrambled early Saturday to assess the damage from a string of powerful storms and tornadoes the night before that killed at least one person at an Arkansas nursing home, caused a roof to collapse at an Amazon building in Illinois and prompted Kentucky’s governor to declare a state of emergency.
A tornado hit the nursing home, Monette Manor in Monette, Ark., at about 8:15 p.m. local time, prompting a large response from the police and emergency workers in the area, according to Marvin Day, the Craighead County judge.
Search-and-rescue workers found one person who had died and five who had been seriously injured, Mr. Day said, correcting an earlier report that at least two people had been killed. Mr. Day said that other residential buildings in the area had also been damaged.
“It’s just really heartbreaking,” he said.
Local news reports also showed that the roof of an Amazon warehouse had collapsed in Edwardsville, Ill., drawing police officers and emergency workers.
Herbert Simmons, the director of the St. Clair County Emergency Management Agency, said late Friday that local officials were responding to an “active scene” at the warehouse. “Right now, our concern is trying to get people who are trapped,” he said, adding that he was not sure how many people might be in the building.
A BBC reporter at the scene said around the same time that about 100 people were believed to have been inside.
Gov. J.B. Pritzker of Illinois said on Twitter that the State Police and emergency management officials were working with local officials and that he would continue monitoring the situation.
Amazon did not immediately respond to a request for comment.
In Kentucky, Gov. Andy Beshear’s official Twitter account said late Friday that he had declared a state of emergency and activated the state police and the Kentucky National Guard to help respond to “major tornado damage.”
Tornadoes are relatively small, short-lived weather events. Scientists are not yet able to determine whether there is a link between climate change and the frequency or strength of tornadoes, in part because they have a limited data record.
Still, researchers say that in recent years tornadoes seem to be occurring in greater “clusters,” and that a so-called tornado alley in the Great Plains — where most tornadoes occur — appears to be shifting eastward.
At least five states were hit by tornadoes on Friday night, including Illinois, Kentucky, Tennessee, Missouri and Arkansas, said Bill Bunting, operations chief at the Storm Prediction Center, part of the National Weather Service.
Mr. Bunting said the tornadoes were part of the same weather system that was wreaking havoc in many parts of the country, causing substantial snowfall across parts of the upper Midwest and western Great Lakes.
The damage in Arkansas came after a severe thunderstorm produced a tornado that was tearing through the region, according to the National Weather Service. As of 9:17 p.m. local time, the storm was near Trumann, Ark., and moving northeast at 55 miles per hour, bringing with it a tornado and quarter-sized hail, the Weather Service said.
On Friday night, the Weather Service had issued a tornado warning for several counties in eastern Arkansas and southeastern Missouri.
“This is what we would call a tornado outbreak, where you have a storm system which produces a number of tornadoes over a large geographical area,” Dan Pydynowski, a senior meteorologist with AccuWeather, said on Friday.
But such a large and powerful system in December is highly unusual, and something the region usually sees in May or April.
“It’s certainly not unheard-of,” he said of tornadoes this late in the year, “but to have an outbreak of this magnitude, with this many tornado reports — it’s a little unusual for this time of year.”
Temperatures in Arkansas and Kansas today were “spring weather,” Mr. Pydynowski said. Highs were in the 70s and 80s. “It was unusually warm, and there was moisture in place. And you had a strong cold front end. These are the ingredients for big storms in the spring, but not in mid-December,” he said.
Tornado warnings were in place overnight, and Mr. Pydynowski said he expected the storm system to move into Ohio, eastern Kentucky and eastern Tennessee.
“Remember, there are people affected by all these tornadoes,” Craig Ceecee, a meteorologist and a graduate student at Mississippi State University, said on Twitter late Friday night as he tracked tornadoes across Kentucky. “Communities being hit hard. And we won’t know how bad it is until morning. We have to think and pray for those being affected.”
Mike Ives contributed reporting.