A massive storm billed as the worst in decades has left vast areas of the United States paralysed by snow and ice.
Hundreds of motorists were stranded and airports and schools were forced to close.
Chicago received up to 17in of snow, with more still possible, and up to 18in fell on Missouri.
More than a foot dropped on northern Indiana and south-east Kansas, while Oklahoma saw similar snowfall. In the north east, parts of northern New York had a foot of snow, while New York City was covered in ice.
In Chicago, the city shut down Lake Shore Drive for the first time in years, and hundreds of motorists were stranded for 12 hours after multiple car accidents on the road.
Raymond Orozco, chief of staff to Chicago mayor Richard Daley, said efforts to rescue motorists were "severely hampered" by snow drifts, high winds and white-out conditions.
More than 200,000 homes and businesses in Ohio were without power, while in excess of 50,000 customers had no electricity in New Jersey and Pennsylvania, which were hit with mostly freezing rain and ice. Federal emergency management agency director Craig Fugate said the agency is on standby with generators, food, water and other supplies to help state and local authorities.
In Oklahoma, rescue crews and the National Guard searched overnight for any motorists who might be stranded along its major roads after white-outs shut down Tulsa and Oklahoma City.
Even Chicago - with its legions of snowploughs and its usual confidence in the face of winter storms - bent under the storm's weight. Not only was driving in and around the city hazardous but Chicago's O'Hare International Airport - a major US hub - was shut until Thursday.
The decision by O'Hare-based airlines to cancel all their flights for a day-and-a-half was certain to have ripple effects at other US airports, said transportation expert Joseph Schwieterman. Hundreds of flights were also cancelled at airports in Detroit, Milwaukee and Tulsa, Oklahoma.