What's the Difference Between a Snowstorm and a Blizzard?
Large swaths of North America are prone to severe winter weather, and sometimes blizzards are produced as a result. It’s tempting to throw the B-word around during heavy snowfall, but there’s actually a specific and technical definition.
Blizzard Vs. Snowstorm
According to the National Weather Service, a blizzard is a combination of three weather events:
- Sustained winds or frequent wind gusts of 35 mph or greater
- Visibility of less than a quarter mile due to large amounts of falling or blowing snow
- Forecasted continuation of the above conditions for three hours or longer
Interestingly, a blizzard does not technically have to involve active snowfall. If there is a large accumulation of snow on the ground already, sustained winds can blow that snow around and reduce visibility to blizzard-level conditions even when no snow is falling. This is called a “ground blizzard”.
A snowstorm, or winter storm, is generally considered less severe due to the lack of high winds and low visibility, but they can still be dangerous, especially when driving or walking on slick surfaces. Winter storms are characterized by near-freezing or below freezing temperatures and “wintery mix” precipitation, which can include snow, sleet, ice and freezing rain. Whether you’re dealing with a snow storm or a blizzard, always be prepared for the severe weather.
Where Do Blizzards Occur?
Blizzards are possible in any area where freezing temperatures and snowfall occur. In North America, blizzards are most common in the Northern Plains, the Midwest and throughout Canada. They also occur in the Northeastern United States, but because snow tends to be wetter and heavier in coastal regions, it’s less prone to being blown around in a way that severely reduces visibility.
What Is a Nor’easter?
While we’re defining winter weather terms, there’s another one that’s often misunderstood: the nor’easter.
Nor’easters are often thought of as powerful snowstorms, but a storm doesn’t have to involve any snow or even occur during winter to qualify as a nor’easter. A nor’easter is a powerful low-pressure system that originates along the Mid-Atlantic coast and features strong northeasterly winds. They’re most common between early fall and late spring, and they often do include paralyzing snowstorms.
Nor’easters generally strengthen as they move up the coast, which makes them particularly threatening to large coastal cities between Washington, D.C. and Boston.
Ordinary blizzards are bad enough, but you can definitely count yourself lucky if you’ve never had to endure a truly historic one. Here are just a few of the most dangerous and destructive blizzards in U.S. history:
- The Great Blizzard of 1888 -- The deadliest winter storm in U.S. history struck as a surprise in mid-March, very late for a blizzard. Up to 50 inches of snow accumulated in the densely populated Northeast, striking New York City, Boston and Philadelphia particularly hard.
- The Knickerbocker Storm -- On January 27 and 28, 1922, an intense blizzard dumped wet, heavy snow throughout the Mid-Atlantic region. Some of the worst damage was in Washington, D.C., where the deluge of snow collapsed the roof at the famous Knickerbocker Theater.
- The Great Midwest Blizzard of 1967 -- This massive snowstorm stretched from the Upper Midwest all the way to Northern New Mexico, but the worst blizzard conditions were confined to Northern Illinois and Indiana. The blizzard paralyzed Chicago for days, burying cars and trapping citizens in homes, schools and workplaces.
- The Storm of the Century -- In March 1993, this blizzard struck along much of the Eastern U.S., affecting 26 states. What began as a cyclone in the Gulf of Mexico grew to become one of the most destructive storms in U.S. history, dumping heavy snow as far south as Florida and causing billions of dollars in property damage.
- Snowpocalypse of 2009 -- This nor’easter swept up the East Coast in December 2009, smashing snowfall records in Washington, D.C., Baltimore and Philadelphia. Several Northeastern cities recorded 24-hour snowfall totals of well over 20 inches.