The epic winter of 2010 - 2011 delivered yet another major pounding to New England yesterday and today, and residents are digging out today from the winter's third record snowstorm. The heaviest snows from this newest onslaught hit coastal New Jersey and New York City, where snowfall rates up to 4 inches per hour were accompanied by hundreds of lightning strikes. The 19.0" inches that fell in New York City's Central Park made it the 8th largest snowstorm for the city in recorded history. When combined with the heavy snows of 1 - 2 feet that fell during the Nor'easter just two weeks ago, January 2011 now ranks as the snowiest January on record in New York City, Newark, Bridgeport, and Hartford. ---------
Why such an unusual number of top-ten snowstorms for the Northeast in recent years? The Northeast has seen an inordinate number of top-ten snowstorms in the past ten years, raising the question of whether this is due to random chance or a change in the climate. This year's record snow storms were all the more unusual, as they came during La Niña conditions in the Eastern Pacific. Is it random chance, or did climate change play role? Well, it could be either, and we simply don't know the answer. A study by Houston and Changnon (2009) on the top ten heaviest snows on record for each of 121 major U.S. cities showed no upward or downward trend in these very heaviest snowstorms during the period 1948 - 2001. It would be interesting to see if they repeated their study using data from the past decade if the answer would change. As I stated in my blog post, The United States of Snow in February, bigger snowstorms are not an indication that global warming is not occurring. The old adage, "it's too cold to snow", has some truth to it, and there is research supporting the idea that the average climate in the U.S. is colder than optimal to support the heaviest snowstorms. For example, Changnon et al. (2006) found that for the contiguous U.S. between 1900 - 2001, 61% - 80% of all heavy snowstorms of 6+ inches occurred during winters with above normal temperatures. The authors also found that 61% - 85% of all heavy snowstorms of 6+ inches occurred during winters that were wetter than average. The authors conclude, "a future with wetter and warmer winters, which is one outcome expected (National Assessment Synthesis Team 2001), will bring more heavy snowstorms of 6+ inches than in 1901 - 2000." The authors found that over the U.S. as a whole, there had been a slight but significant increase in heavy snowstorms of 6+ inches than in 1901 - 2000. If the climate continues to warm, we should expect an increase in heavy snow events for a few decades, until the climate grows so warm that we pass the point where winter temperatures are at the optimum for heavy snow events.
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