A massive winter storm roared into America's heartland today, carrying a paralysing punch of dangerous ice and snow that shut down airports, schools, colleges and government offices.
Ice-covered streets were deserted in Super Bowl host city Dallas, whiteouts shut down Oklahoma City and Tulsa, and more is on the way.
Chicago expects 2ft of snow, Indianapolis an inch of ice, and the north east more ice and snow in what is shaping up to be a record winter for the region.
The worst storm in decades stretched more than 2,000 miles from Texas to Maine, across a third of the country, with nearly 6,000 flights cancelled.
Winds topped 60mph in Texas. In Chicago, public schools called a snow day for the first time in 12 years, and both major airports gave up on flying until at least this afternoon. Thousands of office workers in Chicago's famous downtown Loop district left early to avoid transit troubles.
The storm also led Chicago officials to close the city's busy and iconic Lake Shore Drive while crews tried to plough snow. City officials said the move was temporary but that they could have to close it again if high winds push 25ft waves from nearby Lake Michigan on to the roadway.
Everyone "should brace for a storm that will be remembered for a long time", said Jose Santiago, executive director of Chicago's office of emergency management.
Many cities across middle America began shutting down hours ahead of the snow. Scores of schools, colleges and government offices cancelled activities or decided not to open at all.
In Missouri, more than a foot of snow had fallen by midday, with no end in sight. For the first time in history, the state of Missouri shut down Interstate 70 between St Louis and Kansas City due to a winter storm.
In state capitols across the Midwest and East, lawmakers cut short their working week because of the storm. Normally bustling downtown streets were quiet, and many stores were closed.
Meteorologist Jeff Johnson of the National Weather Service in Des Moines, Iowa, said the storm was sure to "cripple transportation for a couple of days".
"You don't want to get caught out in the rural areas in your vehicle in this storm. It's a good night to stay home," he said.
The leading edge of the storm slammed first into Texas and Oklahoma after moving out of the Rockies.
Both of Oklahoma's major airports were closed, and the state called the National Guard to help rescue workers search for stranded motorists. Outside Tulsa, at the Hard Rock Casino, the snow caused the partial collapse of a roof, but no injuries were reported.
In Texas, thousands of people lost electricity during the frigid conditions. Utility company Oncor reported nearly 27,000 customers without power state-wide, with nearly half of the outages in the Dallas-Fort Worth area.
The storm is expected to roll into the north east, bringing more snow to a winter-weary region. Towns that have been hit by several blizzards since December feared they wouldn't have anywhere to put more snow.
Ice-coated roads were nearly empty in Dallas, where the few motorists who braved the unfamiliar terrain slowed to a crawl as they passed jack-knifed lorries on slick highways. The National Football League managed to stick to its Super Bowl schedule, holding media activities at Cowboys Stadium in suburban Arlington as planned, ahead of Sunday's showpiece game.