Mammoth snow storm pounds central US
Chicago - A massive winter storm among the worst the United States has seen in decades dumped snow, ice and sleet across a huge swath of the country on Tuesday, knocking out power and grounding thousands of flights.
The storm - one of the largest winter storms since the 1950s, according to Nasa - stretched for more than 3 000km from Texas to the northeastern state of Maine, and forecasters warned it could be several days before it abated.
Blizzard, winter storm and freezing rain warnings were issued for more than half of the 50 US states, and tornadoes and major thunderstorms were also predicted along the southern end of the storm in Louisiana and Mississippi.
Officials warned the public to stay at home rather than try to brave the crippling and potentially record-breaking storm.
"Travel will be dangerous and life-threatening due to dramatically reduced visibilities and bitter cold wind chills," the National Weather Service office in Iowa warned.
"If you become stranded expect to spend the entire night in your vehicle as rescuers likely will not be able to reach you."
Dangerously cold temperature
High winds and freezing rain turned roads into deadly ice rinks and knocked down trees and power lines. By late on Tuesday more than 60 000 customers had lost power in Indiana alone, in addition to 22 000 in Ohio, local media said.
Forecasts warned of dangerously cold temperatures, blinding snow and massive drifts as high as 2.4m.
"Lurking behind this impressive winter storm is a powerful shot of Arctic air as a frigid surface high drops down from central Canada," the weather service warned.
Wind chills were forecast to drop to 30 to 50 below in Colorado, Wyoming, Utah, the Dakotas, Kansas, Iowa, Nebraska, Minnesota and even parts of Texas.
States of emergency were declared in Illinois, Indiana, Missouri and Oklahoma and the National Guard was called out to help rescue stranded motorists.
Emergency warming shelters were also set up for people whose homes lost power.
10 000 flights cancelled
Thousands of schools and government offices were closed and many businesses shut down early as well.
Snow had already piled up to as much as 15 to 48cm in parts of Oklahoma, Texas, Wisconsin, Minnesota, Missouri and Kansas by late Tuesday afternoon, the National Weather Service reported.
FlightAware reported that airlines grounded nearly 6 500 flights on Tuesday - about 20% of US commercial flights - and protectively cancelled another 3 600 on Wednesday.
Dallas-Fort Worth International Airport, a major hub, was closed briefly on Tuesday morning due to the ice storm and delays were averaging about three hours once it reopened.
Most of the airlines at Chicago's O'Hare airport - one of the busiest in the world - stopped operating after the blizzard set in Tuesday afternoon and said they "will have limited or no operations" on Wednesday, the airport said.
Chicago was expected to be among the hardest hit with up to 60cm of snow and officials warned ploughs would not be able keep the streets clear, making side streets impassable.
Gusts up to 95km/h could also lead to flooding along the lake shore as waves build up to 7.6m.
Shovelling snow can be deadly
The local weather service said the "dangerous, multifaceted and life-threatening winter storm" with high winds and heavy snowfall would make travel "impossible" at times.
The agency also warned that shovelling sidewalks during such a significant snowfall can be deadly, noting that more than 40 people died of heart attacks in the aftermath of a 1999 blizzard in Chicago.
"Do not underestimate the task at hand," it said.
Rachel Hansen, aged 35, got an early start on shovelling her walkway on Tuesday so she'd have less work to do in the morning.
"It's only been a couple hours and look how much there is," she said as she dug through several inches of heavy, wet snow.
The city of Tulsa, Oklahoma, was reported at a near standstill on Tuesday after a record 33cm of snow was blown into deep drifts and collapsed the roof of a local casino.
"There are hundreds and hundreds of cars stranded in the city, from private to emergency vehicles," Paul Strizek of the city's public works department told the Tulsa World.
St Louis, Missouri, was another major trouble spot as snow fell over a thick sheet of ice and sleet. One woman was reported killed when her car spun out of control on a rural Missouri highway.