Plunging temperatures and extreme weather have been causing chaos in parts of Canada and the US.
People have been shivering in temperatures as low as -52 degrees Celsius in Canada's Quebec City. Ottawa and Montreal were also badly affected.
New Jersey, New York, Connecticut and Massachusetts were among the US states hit by Arctic conditions. New York city was covered in a blanket of snow.
Schools were closed, doors froze to their frames and flights were shelved.