Forty-eight people are reported to have died as a result of the weekend storms that hit the midwest of the United States.
Thousands of people spent a second night in airports waiting for snow to be cleared, after near-record amounts had fallen on cities such as Chicago and Buffalo.
In Canada, similiar storms caused at least eight deaths in the east, and hundreds of flights were cancelled at Pearson International airport in Toronto.
From the newsroom of the BBC World Service