Dozens of people have died as a major frost strikes North America.

At least 38 deaths have now been attributed to the severe Arctic cold that is still wreaking havoc on the United States and Canada.
Officials believe 34 people died across the United States, with Buffalo, New York, being the hardest hit.
Four people were killed in Canada after a bus rolled over on an icy road in Merritt, in the western province of British Columbia.
The extent of the winter storm has been extraordinary, extending from Canada to the Rio Grande.
Forecasters predict that the storm will weaken over the following three days, but it is still advised to avoid travel unless necessary.
The storm has been wreaking havoc for days, but power has been gradually restored following previous blackouts.
According to the Associated Press, fewer than 200,000 customers were without power as of Sunday afternoon EDT, down from a peak of 1.7 million.
Thousands of flights have been canceled, preventing many people from celebrating Christmas with their families.
On Sunday, more than 55 million Americans were still under wind chill warnings.
There were other storm-related deaths in Vermont, Ohio, Missouri, Wisconsin, Kansas, and Colorado. Temperatures in South Florida dipped so low that iguanas froze and fell from trees.
Montana, in the western United States, has been affected the hardest by the cold, with temperatures plummeting to -50F. (-45C).
The provinces of Ontario and Quebec are facing the brunt of the storm in Canada.
On Sunday, about 120,000 Quebec consumers were without power. Some households may not be reconnected for several days, according to officials.