DC Area's wild snowfall trends

 

A snowy morning in Bethesda, Maryland

As DC enters the final days of February, the end of "meteorological winter" is almost here on February 29. Although the nation's capital had a snowier than average January, the rest of the winter has produced very little snowfall. My colleagues and I on the WUSA9 Weather Team don't expect any more snowfall this month, making this the ninth consecutive February with below average snowfall. That underscores the need to discuss some key winter weather trends in the DC Metro Area.

The nation's capital has seen above average snowfall in only 5 of the last 20 winters, according to NOAA. Despite that trend four of DC’s 10 largest winter storms have occurred just since 2003. In fact, DC’s snowiest winter on record was in 2009-2010 and featured two of its largest winter storms. February 2010 finished as DC’s second snowiest February and second snowiest month overall, with 32.1”. More than half of that total came with “Snowmageddon” (17.8”). 

Seven of DC’s 10 snowiest months ever owe their place on that memorable list in large part to having had one of DC’s 10 largest snowstorms. For example, January 1928 ranks as DC’s third snowiest month with 31.5”, with 28” of that during the "Knickerbocker Storm," DC's largest snowstorm on record.

While meteorological winter spans December, January and February, DC averages accumulating snowfall in the five consecutive months starting in November. There have been several examples in recent years of heavier snowfall occurring either in late fall or March. March was DC’s snowiest month of the year on five occasions since the 2008-2009 winter.

These trends were factored into NOAA’s updated data set for what constitutes “average” weather conditions. NOAA updated its running 30-year period to 1991-2020, replacing 1981-2010.  As a result, the nation’s capital averages less snowfall than it did previously.  That’s largely due to the fact that the 1980s were a snowier decade than the 2010s. 

Another factor was the increased urban heat island effect as Washington, D.C. has become more urbanized and, thus, warmer than in previous decades.  Snow lovers shouldn’t fret, however, as the right ingredients need to come together only once to create a major winter storm.

DC’s snowiest months with any of the Top 10 snowfalls that occurred in those months

1. 35.2” (February 1899): 20” (February 12-14)
2. 32.1” (February 2010): 17.8” (February 5-6)
3. 31.5” (January 1928): 28” (January 27-29)
4. 30.6” (February 1979): 18.7” (February 18-19)
5. 28.7” (February 2003): 16.4” (February 16-18)
6. 24.4” (January 1935)
7. 23.8” (January 1996): 17.3” (January 7-9)
8. 22.6” (January 1918)
9. 21.0” (February 1983): 16.6” (February 10-11)
10. 20.8” (January 1987)

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DC’s snowiest winters (Source: NOAA)

1. 56.1” (2009-2010)
2. 54.4” (1898-1899)
3. 46.0” (1995-1996)
4. 42.5” (1921-1922)
5. 41.7” (1891-1892)
6. 41.0” (1904-1905)
7. 40.4” (2002-2003, 1957-1958)
9. 40.3” (1960-1961)
10. 39.8” (1910-1911)