An Arctic blast has gripped North America over the last few days. Bitter weather and icy winds have dragged the temperatures down over many eastern parts of both Canada and the USA.
Snow has added to the misery, with more than 250 mm falling in parts of Michigan this week. The snow is known as 'lake-effect snow' because the air picks up moisture as it passes over the Great Lakes and delivers it as snow to the opposite coast. This is a regular hazard of the winters in North America.