Posted by: pyeager | January 11, 2011

Blizzard Is Not Synonymous with Heavy Snow

Pardon me if you’ve heard me say this before, but a blizzard has to do with the intensity of the event, not the amount of snow that falls.

A storm that produces 100 inches of snow is not automatically a blizzard, and a blizzard can technically occur with absolutely no snow falling from the sky.

According to the National Weather Service, a blizzard is when the following conditions are met:

  • Snow or blowing snow reduces visibility to under 1/4 of a mile with a sustained wind (or frequent gusts) to at least 35 mph for a minimum of three hours.

Again, some of the heaviest snow storms occur with little or no wind to speak of; therefore, they are not blizzards.

On the other hand, some of the lowest visibility occurs when a powdery snow on the ground is blown by howling winds, creating blizzard conditions, even if no snow is falling from the sky.

A blizzard is intensity, not accumulation.

Of course, if you’d have read my book (Weather Whys: Facts, Myths, and Oddities), then you’d have already known that.

I wonder what else you’d already know if you’d have picked up a copy. Of course, it’s never too late….

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Responses

  1. One of my wx pet peeves…as well.
    Blizzards are hi-wind events where the visibility is severely restricted by snow.

    From the AMS glossary…
    “In popular usage in the United States and in England, the term is often used for any heavy snowstorm accompanied by strong winds.”

    http://amsglossary.allenpress.com/glossary/browse?s=b&p=30

    Adding further to the confusion is the NWS threshold for issuing a blizzard warning…which states visibilities ’1/4 mile or less.’

    http://www.crh.noaa.gov/lot/severe/wxterms.php

    WFO BOS gets it wrong.

    http://www.erh.noaa.gov/box/warningcriteria.shtml


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