The earliest use of the word seems to be in 1829, but at first the word didn't mean a violent snowstorm. It seemed to mean to hit something or to punch. Col. Davy Crockett (yes, that Davy Crockett) used the word blizzard not for a winter storm, but as a figurative threat to some dinner companions who were poking fun at him. The Century Dictionary suggests that blizzard is related to the word blaze. So in reacting aggressively, Davy Crockett was using the word to say he was prepared to blaze away at them, or punch them. On another occasion, Crockett also used the phrase taking a blizzard to describe gunshots at a deer. The first time blizzard was used to describe the weather appeared in an Estherville, Iowa, newspaper in March 1870. The paper was referring to the city getting PUNCHED by a strong winter storm.
Blizzards are dangerous winter storms that are a combination of blowing snow and wind resulting in low visibilities. Officially, the National Weather Service defines a blizzard as a storm which contains large amounts of snow OR blowing snow with winds in excess of 35 mph and visibilities of less than 1/4 mile for an extended period of time (at least 3 hours). When these conditions are expected, the National Weather Service will issue a blizzard warning.