By Greg McCune
CHICAGO (Reuters) - The upper Midwest was recovering on Saturday from an unusual autumn wallop from a fierce snowstorm that trapped dozens of people in vehicles in western South Dakota and a swarm of tornadoes that left at least 15 people injured in rural Nebraska and Iowa.
More than 80 motorists remained stranded in western South Dakota after a blizzard rolled out of the Rocky Mountains and dumped up to three feet of snow on parts of the Northern Plains.
"Our priority right now is to get those people to a warm location," said Alexa White, spokeswoman for the Rapid City-Pennington County Emergency Management Office in South Dakota. "Many of them are out of gas in their vehicles."
To the east, emergency responders combed through debris in Iowa and Nebraska after 18 reports of tornadoes touching down overnight, including some cutting a swath as wide as a mile.
Fifteen people were injured in Wayne, Nebraska, including one man who suffered broken bones when his pickup truck was hit by a tornado, according to Nebraska emergency management spokeswoman Jodie Fawl.
Fawl said the twister did millions of dollars of damage - pummeling a local airplane hanger, farm implement supply businesses and several homes.
"There are corn and soybean fields littered with debris all over the place from houses and buildings that were damaged," Fawl said.
In Iowa, Woodbury County Emergency Management Director Gary Brown said that several tornadoes touched down, destroying more than 20 homes and damaging 40 to 60 farms. There were no serious injuries, he said.
It was unclear how many tornadoes touched down in all, said Billy Williams, a National Weather Service meteorologist in Sioux Falls, South Dakota. The number of 18 listed by the weather service could include duplicate reports.
None of the tornadoes hit a major populated area, officials said.
The snowstorm in South Dakota left four-wheel-drive vehicles, snow plows and even rescuers in fire trucks stuck, White said. Fire stations opened as emergency shelters.
About 380 miles of Interstate 90 were closed from western South Dakota to northeastern Wyoming, according to transportation departments in both states.
The National Weather Service, which is running on a reduced staff because of the federal government shutdown, issued blizzard and severe winter storm warnings across the northern part of the Great Plains for Saturday.
It also warned of a risk of severe thunderstorms later on Saturday in nine states stretching from Wisconsin to Arkansas, although the threat of tornadoes was diminished.
It said the storm would continue to produce widespread heavy snow and strong winds through late Saturday in central South Dakota. The Black Hills area has seen near record snowfall accumulations.
"It's not normal this time of year, but it is not unheard of," said Cory Martin, meteorologist for the National Weather Service in North Platte, Nebraska. "But this amount of snow for an October storm is on the higher end."
It is also rare for tornadoes to strike in the fall. The most active season is usually in the spring or early summer.
(Additional reporting by Noreen O'Donnell; Editing by Vicki Allen)