Though the summer heat and humidity makes it seem like a lifetime ago, the record-breaking snows in the eastern U.S. last winter are not something we will soon forget. Several feet of powder fell on most of the Mid-Atlantic region during February 2010, and this week a study from Columbia University’s Lamont-Doherty Earth Observatory gives us new insight into what caused the freaky weather.
A rare combination of weather — not climate — patterns seems to be the culprit. El Niño produced abnormally wet conditions in the southeastern U.S.; a negative North Atlantic Oscillation pushed frigid Arctic air down from the North. This collision of moisture with abnormally cold air led to more than six feet of snow over the region between December 2009 and February 2010.