Blizzards

Blizzards are the most severe winter storm, with blowing snow, high winds, and low temperatures. Different countries have different classification systems for blizzards. The U.S. National Weather Service categorizes a blizzard as a winter storm with sustained winds or frequent gusts of 35 miles per hour or greater, and enough falling or blowing snow to frequently reduce visibility to less than a quarter of a mile. Temperatures are 20 degrees F or lower. These conditions prevail for at least three hours. A “severe” blizzard has winds of 45 miles per hour or greater and temperatures at 10 degrees F or below.

Blizzards are caused by extra-tropical storms that originate outside the tropics and dominate the weather in the mid-latitudes of the world from [Page 146]autumn to ...