A blizzard warning (SAME code: BZW) is a hazardous weather statement issued by Weather Forecast Offices (WFO) of the National Weather Service (NWS) in the United States, which indicates heavy snowfall accompanied by sustained winds or frequent gusts of 35 mph (56 km/h) or greater are forecast to occur for a minimum of three hours. A blizzard tends to reduce visibilities to 1⁄4 mile (400 m) or less.
A severe blizzard warning is a variation issued in some cases of winds above 45 mph (72 km/h) and temperatures below 10 °F (−12 °C). Most local weather offices will activate and broadcast the SAME alarm tone on relevant NOAA Weather Radio stations for both varieties of warning. When the Wireless Emergency Alerts system was launched in 2012, blizzard warnings were initially sent as alerts to mobile phones; this practice was discontinued in November 2013.
In Canada, comparable warnings are issued by Environment and Climate Change Canada through the Meteorological Service of Canada (MSC). As of 2010, blizzard warnings issued by local MSC forecast offices are based on sets of regionally determined criteria:[1]
- National warning below tree line – warning requires sustained winds of 40 km/h (25 mph) or greater with widespread reductions in visibility to 400 m (0.25 mi) or less from blowing snow or a combination of blowing and falling snow to occur at least four hours.[2]
- Northern (Arctic) warning above tree line – criteria are the same as national warning but for blizzard conditions forecast to occur for at least six hours.[2]
The warnings are relayed by Weatheradio Canada and media outlets like The Weather Network.
- ^ "What is a blizzard?". Archived from the original on April 2, 2012.
- ^ a b "Environment Canada – Weather and Meteorology". ec.gc.ca. Retrieved 7 December 2015.