A severe storm lasting four or more hours. It is characterized by low temperatures, strong winds and poor visibility due to blowing snow. True blizzard conditions are most common on the prairies of Canada and the United States. Blizzards are a rare occurrence on the west coast and in Atlantic Canada. The Environment Canada has listed the following general criteria for issuing blizzard warnings in Canada: visibility less than 1 kilometer, wind speeds greater than 40 kilometers per hour, high windchill values.