At least nine people have died and tens of thousands have been left without electricity in the US Midwest due to a fierce snowstorm.
Snow storms in the central US have left at least nine people dead and tens of thousands without electricity.
At least three people in Minnesota, three in Wyoming and one each in Texas, Kansas and Wisconsin died in traffic accidents stemming from the storm.
The severe weather has caused hundreds of accidents, and reached as far south as Texas - where there was a 50-vehicle motorway pile-up.
The fatal Texas pile-up reportedly involved 50 cars.
The storm, bringing ice and snow, has also felled trees and power lines. Dozens of flights have been cancelled.
More heavy snow has been forecast for Minnesota, Wisconsin and Michigan on Sunday as the storm heads north.
More heavy snow has been forecast as the storms move into the Great Lakes region bordering Canada.
Parts of Wisconsin have already had a foot (30cm) of snow, and up to another foot was forecast for Sunday in north-eastern Minnesota, the National Weather Service said.
Multiple-vehicle pile-ups closed major highways in the plains states over the weekend.
I can see the snow moving basically sideways Wayne Hoepner, meteorologist,Grand Rapids, Michigan
In Minnesota alone, there were more than 300 road accidents and three deaths.
Radar showed snow falling across much of Wisconsin and eastern Minnesota on Sunday and moving into parts of Michigan and Indiana.
Miserable Christmas
"Everything is just an ice rink out there," Steve Selby, sheriff's sergeant in Rock County, Wisconsin, said on Sunday morning.
Three other people died in accidents in Wyoming, and one each in Texas, Kansas and Wisconsin.
Blackouts
The fatality in Texas came in a chain-reaction pile-up on Interstate 40.
The weather system also spread heavy rain on Sunday from the south-east to the lower Great Lakes.
At least 16 people were taken to hospital, two with life-threatening injuries.
Multiple-vehicle pile-ups closed parts of several major highways on Saturday in the plains states.
Many in the pile-up were holidaymakers, including families with small children not dressed for the weather, police said.
The weather has brought traffic to a standstill in parts of the Midwest
The BBC's Matthew price in the US says Americans expect bad weather at this time of year and the country has the resources to cope.
Wind gusting to more than 50mph (80km/h) uprooted trees in parts of Michigan.
But for some the fierce winter is making it a miserable Christmas, our correspondent adds.
"I can see the snow moving basically sideways," weather service meteorologist Wayne Hoepner said in Grand Rapids.
More than 11,000 homes and businesses were without power in Wisconsin on Saturday because of the freezing rain, ice, gusty winds and heavy snow, utilities said.
Some 114,000 customers were without power on Sunday morning in Michigan, and in Illinois about 58,000 customers were blacked out in the Chicago metro area.
Christmas presents
The fatality in Texas came in a chain-reaction pile-up involving more than 50 vehicles, including several tractor-trailer rigs, on Interstate 40, police said.
Sgt Michael Poston said at least 16 people were taken to hospital, two with life-threatening injuries.
Many in the pile-up were holidaymakers, including families with small children not dressed for the weather, Sgt Shawn McLeland said.
Other drivers spotted them and opened Christmas presents to provide warmer clothing for the children.
Authorities believe the pile-up, which shut down the highway for most of the day, was caused by very poor visibility.
