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Posted at 10:45 AM ET, 01/14/2010

What makes a big snowstorm a blizzard?

Some of Washington's biggest storms not blizzards

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"BLIZZARD!"... The word strikes fear into the hearts of "snow country" residents, particularly Midwesterners, who are much more accustomed to its wrath, and thus apt to take warnings more seriously. Although Washingtonians also take snow seriously (maybe too seriously, I would say), many make little distinction between a garden-variety snow forecast and a blizzard warning.

In both cases we buy out all the grocery shelves but do little else, such as preparing our cars, checking our homes, or protecting our bodies. The result is that when the rare blizzard does hit here -- some would say it never does -- there is unnecessary hardship.

Where did the word "blizzard" come from? And did our big December storm qualify as one?

It may have had even earlier beginnings, but the term "blizzard" was first noticed in 1870 as a reference in the Northern Vindicator newspaper (Estherville, Iowa) to the great snowstorm of March of that year. Subsequently, according to the (then) U.S. Weather Bureau, a blizzard was defined as a severe storm with high winds, very low temperatures (generally under 20° F), and falling and/or blowing snow, creating near-zero visibility.

The current definition of a blizzard, a la National Weather Service (NWS), has been relaxed significantly. It is a storm with snow and/or blowing snow reducing visibility to 1/4 mile or less for three hours or longer AND sustained winds of 35 mph or greater or frequent gusts to 35 mph or greater, with no temperature requirement. (Contrary to popular belief, a blizzard need not be accompanied by heavy snow or even falling snow, since, under the right conditions, just a few inches of newly fallen snow may qualify.)

Technically, then, the storm of Dec.18-19, 2009, was not a blizzard, although at one point during the storm the NWS did issue a blizzard warning for much of the metro area. The warning was dropped, however, when wind speeds failed to exceed the required threshold.

The combination of elements in a blizzard (particularly under the old definition) can be deadly to those left unprotected. Frostbite sets in rapidly and, since the air is filled with minute snow particles, breathing itself can become difficult. Also, due to the "white out" effect, people can become disoriented in open areas, such as farmland. Tragically, young children and even adults, unable to find their way, are occasionally found frozen to death only yards from their front doors.

Based on (either the old or new) definition, local residents have seen few storms during the last 50 years that would qualify as a blizzard. Longtime locals will, however, remember the stand-outs, such as the storms of Feb. 15, 1958, Jan. 29-30, 1966, Jan. 6-8, 1996, and possibly a few others. Blizzards by most any standards, each of these dumped more than a foot of wind-driven, powdery snow, which was transformed into such mountainous drifts that some rural homeowners were isolated for many days.

In looking back still further in the record books, we find that the Great Blizzard of February 1899 was probably the only other storm of blizzard proportions in the 139-year (official) Washington weather record. (However, if you think others qualify, let us know.) The 1899 storm was likely the granddaddy of all D.C./Maryland/Virginia blizzards on record due to its long duration (three days), intensity (almost two feet of snow on the level and drifts many times that), and near-zero cold. (Unofficial records tell of even more ferocious winter storms blasting the mid-Atlantic during colonial times, such as the Washington-Jefferson Storm of January 1772, which left "three feet of snow on the level.")

For those wondering, neither the fabled Knickerbocker Storm of January 1922 (which occurred 150 years to the day after the fabled Washington-Jefferson Storm), nor the 18-20 inch "Presidents' Day Storm" of February 1979, nor the one in 2003 were considered blizzards by the NWS. Records reflect that all of these had relatively little wind. However, the 1922 storm caused over 100 deaths when the roof of Washington's old Knickerbocker Theater collapsed under 28 inches of snow (the biggest snowstorm on record here).

And finally, for the real weather trivia buffs, it is curious to note that our local 24-hour snowfall record (25 inches) equals or exceeds those of such icebox cities as International Falls and Duluth, Minn., and many other northern cities. This, despite the fact that those northern cities usually receive far more snow each year than our 15-25 inch annual average.

All of the above aside, when it snows in our area more than, say, eight inches (with or without wind), only meteorologists will argue whether or not a blizzard has occurred. To the rest of us, who must walk in it, work in it, and especially drive in it, it is a blizzard!

By  |  10:45 AM ET, 01/14/2010

Categories:  Winter Storms

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