While snowstorms are a common occurrence in the snow-prone areas of the world during the winter months, typically it is nothing more than a nuisance to those caught in it. However, sometimes these simple snowstorms form into much larger and far more stronger storms which can grind entire regions to a halt through a mixture of snow, wind, and bitterly cold temperatures.
This term is often misused in the media to describe strong winter storms. In reality, there are some rather stringent criteria that need to be met in order for a winter storm to be called a "blizzard."
What is a Blizzard?
According to the U.S. National Weather Service, a blizzard is officially deemed so when conditions meet the following:
- sustained winds of 35 miles per hour;
- blowing snow that reduces visibility to below 1/4 mile; and
- conditions last for three hours.
Environment Canada has a slightly different definition, and those criteria are;
- winds of 40 kilometers per hour;
- visibility of less than 1 kilometer;
- wind chills of -25C or below; and
- conditions last for four hours.
Other regions of the world have their own definitions, some more lax than either the Canadian or US ones. However, generally the idea is about the same.
How Do Blizzards Form?
According to meteorologist Al Peterlin in a recent article on Scholastic.com on snowstorms, blizzards form when a strong high pressure system interacts with a strong low pressure system. The high when positioned right will bring colder air from more northern climes into the storm, while the low draws in moisture. The significant difference in air pressure causes air to move faster between the two systems, causing the strong winds.
Due to the fact that conditions need to be perfect for such an interaction to happen, and that the occurrence of such a strong high and low pressure system close enough together is not a common occurrence, blizzards are commonly a once in a few year event for most locations around the world.
Where are Blizzards Most Common?
These super snowstorms can occur just about anywhere, all that is needed is strong winds and heavy snows. However, there are areas that are more prone to these storms than others. Across the North American continent, blizzards occur most frequently in the Northeast, the Great Plains, and across the Intermountain West in the United States.
In Canada, the same storms that affect the Northeast US often slam into the Canadian Maritimes, and the storms across the Great Plains can extend into the Prairie Provinces as well. Worldwide, Russia is also considered a hot spot for these events, as well as Northern parts of Europe.
What are Some Memorable Blizzards?
Perhaps the earliest of these that is most commonly brought up is the Blizzard of 1888, which struck the Northeast in March of that year. The storm dumped some 3 to 4 feet or more of snow in New Jersey, New York, Massachusetts and Connecticut, and snow drifts in some cases were 50 feet high. The storm shut the region down for a week, and 400 people died.
Another storm occurred nearly to the day 105 years later. Called "the Storm of the Century," this 1993 storm dropped copious amounts of snow from Alabama and Georgia into the Northeastern US and Canada. While most did not see the massive amounts of snow common with many blizzards, this was known for its expansiveness.
Finally, the Blizzard of 1996 probably ranks in many's mind as the worst across the Mid-Atlantic. That January snowstorm set snowfall records in many metropolitan cites, where two to three feet of snow fell. It is often argued this was not a blizzard as it did not meet the criteria in many locations.
Sources: "Biggest Snowstorms in the United States: From 1888 to Present", NWS Milwaukee website, unknown date
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