Blizzard warning

A blizzard warning is issued by the National Weather Service (NWS) in the United States when heavy snowfall combined with sustained winds of 35 mph (56 km/h) or more for at least three hours is expected. This results in reduced visibility to less than 1/4 mile (400 meters). Severe blizzards may have winds exceeding 45 mph (72 km/h) and temperatures below 10°F (-12°C). Warnings are broadcasted via NOAA Weather Radio, though mobile alerts were discontinued in 2013.

In Canada, Environment and Climate Change Canada issues comparable warnings through the Meteorological Service of Canada. These include two categories: national warnings below tree line requiring winds over 40 km/h (25 mph) and reduced visibility for at least four hours, and northern warnings above tree line with similar conditions lasting six hours or more.

Examples provided illustrate detailed forecasts, impacts, and safety measures for blizzards in Duluth, Minnesota, and Toronto, Ontario. Both emphasize hazardous travel conditions, advising restricted movement unless essential, carrying emergency kits, and staying sheltered if stranded.

Further information can be found through the National Weather Service and related glossaries.