March 3, 2013

Twice as many extreme snowstorms - but...

Twice as many extreme snowstorms... but, total snowfall is shrinking! 

The United States has been walloped by twice as many of the most extreme snowstorms in the past 50 years than in the previous 60 years, according to an upcoming study on extreme weather by leading federal and university climate scientists. This also fits with a dramatic upward trend in extreme winter precipitation — both rain and snow — in the Northeastern U.S. charted by the National Climatic Data Center. 
Yet the Global Snow Lab at Rutgers University says spring snow cover in the Northern Hemisphere has shrunk on average by 1 million square miles in the past 45 years.
And an upcoming study in the Journal of Climate says computer models predict annual global snowfall to shrink by more than a foot in the next 50 years. The study's author said most people live in parts of the United States that are likely to see annual snowfall drop between 30 percent and 70 percent by the end of the century…. 
Ten climate scientists say the idea of less snow and more blizzards makes sense: A warmer world is likely to decrease the overall amount of snow falling each year and shrink the snow season. But when it is cold enough for a snowstorm to hit, the slightly warmer air is often carrying more moisture, producing potentially historic blizzards.
"Strong snowstorms thrive on the ragged edge of temperature — warm enough for the air to hold lots of moisture, meaning lots of precipitation, but just cold enough for it to fall as snow," said Mark Serreze, director of the National Snow and Ice Data Center. "Increasingly, it seems that we're on that ragged edge."
[Washington Post]

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