The Weather Notebook: True Blizzard

True Blizzard
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Most of you know what a blizzard is. Even if you've spent your whole life in warm Florida, you can picture it now: howling winds, bitter cold, and so much snow that all you can see is white. This certainly sounds like nasty weather, but when officials at the National Weather Service issue a blizzard warning, they've got something more specific in mind.

Hi, I'm Bryan Yeaton and this is the Weather Notebook.

To qualify as a blizzard at the NWS, a winter storm has to pass three tests:

First, the wind has to be sustained or gusting frequently to more than 35 miles an hour. Second, there has to be enough snow either falling or blowing across the ground to reduce visibility below a quarter of a mile. That's about three city blocks. Finally, these conditions have to persist for at least three hours. There once was a requirement that temperatures had to be below 20 degrees Fahrenheit, but that was dropped a few years ago.

While we know when to call a storm a blizzard, we don't really know exactly where the term "blizzard came from. Some colonists in Virginia used the term "blizz" to mean any bad weather--rain or snow--that arrived on gusty winds. Germans had the word "blitz" for lightning, which later came to mean any sudden assault. By the 1870s, the term "blizzard" began to show up in Midwestern newspapers. The new word arrived just in time. In 1886 the Midwest suffered one of its worst snowstorms ever. Two years later, in March of 1888, New York City endured 21 inches of snow, temperatures below zero and winds gusting close to hurricane force. Now that's a blizzard no matter how you slice it.

The Weather Notebook is a production of the Mt. Washington Observatory and is supported, in part, by the National Science Foundation.