A blizzard is a severe snowstorm characterized by strong winds and low temperature. By definition, the difference between blizzard and a snowstorm is the strength of the wind. To be a blizzard, a snow storm must have sustained winds or frequent gusts that are greater than 35 mph with blowing or drifting snow which reduces visibility. Snowfall amounts do not have to be significant.
Blizzards can bring near-whiteout conditions, and can paralyze regions for days at a time, particularly where snowfall is unusual or rare.