DisastersThe causes of massive snow storms
Three storms spanning from December to February in the winter of 2009-10 had dumped a whopping 54.9 inches of snow on the Baltimore-Washington area; the snowfall broke a seasonal record first set in 1899; Snowmaggedon, as the winter was dubbed, entered the history books as the snowiest winter on record for the U.S. East Coast
In the quiet after the storms, streets and cars had all but disappeared under piles of snow. The U.S. Postal Service suspended service for the first time in thirty years. Snow plows struggled to push the evidence off of major roads. Hundreds of thousands of Washington, D.C. metropolitan residents grappled with the loss of electricity and heat for almost a week.
By 10 February 2010 the U.S. National Weather Service reported that three storms spanning from December to February in the winter of 2009-10 had dumped a whopping 54.9 inches of snow on the Baltimore-Washington area. The snowfall broke a seasonal record first set in 1899. Snowmaggedon, as the winter was dubbed, entered the history books as the snowiest winter on record for the U.S. East Coast.
A NASA release reports that two years later, scientists are still searching to identify the unique set of conditions that enabled storms of this magnitude to occur. To determine a direct cause to infrequent but major winter storms, Siegfried Schubert and colleagues Yehui Chang and Max Suarez — all of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, became detectives.
Schubert is a meteorologist and senior research scientist for Goddard’s Global Modeling and Assimilation Office (GMAO). Using a computer model that simulates the atmosphere, called the Goddard Earth Observing System Model, Version 5 (GEOS-5), Schubert pieced together the meteorological whodunit of 2010’s ‘Snowmaggedon.’
“There are things that we know that affect storminess over the U.S.,” Schubert said. “One is when there is an El Niño, which tends to favor more storms. Given the connection between El Niño and sea surface temperatures, we thought we’d actually do a modeling study to see if we could pinpoint the role of sea surface temperatures in driving the snowstorm
Warmer Pacific can mean stormy Atlantic
El Niño is an ocean-atmospheric climate pattern characterized by unusually warm sea surface temperatures and heightened rainfall in the central and eastern tropical Pacific. The increased rain occurs when warm sea surface temperatures heat the surrounding air, which then rises and condenses into rain clouds. The end result of these changes in the tropics is a shifting of the extra-tropical air currents, or jet streams. Changes in the jet streams can then alter storm paths around the globe.
Over the United States, El Niño tends to produce an unusual eastward extension of the Pacific jet stream and storminess across the southern tier of states. Using the GEOS-5 model,
