The BBC's Mark Connolly: "At least six people have died in traffic accidents"

Hundreds of airline flights have been cancelled and many roads are blocked or dangerous.

Some areas have declared emergencies, banning unnecessary travel.

Meteorologist Matt Crowther: "The have gotten 20 inches of snow"

By Saturday evening, the storm had dropped 17in (43cm) of snow at Chicago's Midway Airport.

Snow was 13in (33cm) deep in western Indiana's Parke County, and 10in (25cm) of new snow had fallen in south-western Ohio and Eldora, Iowa.

Wind gusting to 40mph (64kph) created blizzard conditions and snow ploughs in northern Indiana's LaGrange County were taken off the roads because snow was drifting up to 8ft (2 meters) deep.

Icy roads are believed to have contributed to at least six deaths in road accidents.

Emergency declared

Arctic sea mist engulfs a ferry en route to Portland, Maine

More than 50 of Indiana's counties and cities declared snow emergencies, banning unnecessary travel.

Thousands of travellers found themselves stranded as hundreds of flights through major Midwest airports were called off.

Cancellations caused more delays and cancellations elsewhere across the country, including Denver and New York City's three major airports.

In Florida, tornadoes and severe thunderstorms destroyed and damaged homes, flipped cars and left thousands without electricity as severe weather from the same storm system rolled across northern areas of the state.