Icy American Christmas storm claims at least 19 lives

19 deaths have been linked to the icy grip of a massive winter storm in the United States, which has affected at least 200 million Americans.

While Malta prepares itself for a sunny Christmas Day, with temperatures forecasted to 20°C on Christmas Day, the US National Weather Service (NWS) said its Friday map "depicts one of the greatest extents of winter weather warnings and advisories ever".

More than 1.5 million in the USA are without power and thousands of flights were cancelled on Friday, as the storm covered some 3,200 kilometres, from Texas to Quebec.

A bomb cyclone, when atmospheric pressure plummets, has brought blizzard conditions to the Great Lakes on the US-Canada border.

In Canada, Ontario and Quebec were bearing the brunt of the Arctic blast, with power cut to hundreds of thousands.

Temperatures in Elk Park, Montana, dropped to -45°C, while the town of Hell, Michigan, has frozen over.

Heavy snowfall was forecasted in areas of Pennsylvania and Michigan and Buffalo, New York, was expecting at least 89cm of snow.

A number of the storm-related fatalities have involved road traffic accidents, including a 50-car pile-up in Ohio that killed four motorists. Another four died in separate crashes in the state.

Utilities throughout the Tennessee Valley were implementing rolling blackouts to save power.

The NWS says more than 100 daily cold temperature records could be tied or broken over the next few days.