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Posted at 09:07 AM ET, 03/04/2013

March snow in Washington, D.C.: Precedent exists for ending winter with a bang


Ski-sailing by the Washington Monument, March 14, 1993. The day after the 1993 Superstorm. (Washington Weather)
With the Snowquester storm in the forecast Wednesday, history shows us big March snow events can and do happen at the close of winter, even in seasons with little prior snow.

March snow in Washington tends to be hit or miss, and we currently average 1.3 inches per year during the month. Over 60 percent of the 125 full seasons seasons on the snow record have seen accumulating snow in March or later. Thirty-percent of those seasons have brought 4” or more in March and April.

The most snow D.C. has ever seen on one day in March is the 11.5” on the 29th in 1942. The largest March snowstorm on record is 12 inches, way back on the 27th-28th of 1891.

When it comes to monthly snow records, 19.3 inches is the March high mark in 1914. The most that has fallen at the current location (National Airport since 1946) is the 17.1 inches during 1960.

Seeing as we should accomplish the accumulation task with ease given the forecast for Wednesday’s Snowquester storm, why not shoot for a record?! Well, at least we can take a peek at what we might need to get.


March snowfall benchmarks. The storm data is based on official climate records by day, though an event like that in 1937 may present a question as to whether it was one or two storms. I strongly believe it was one. Investigations via available tools such as historical daily maps have helped in the compilation. (Monthly data via NWS Baltimore/Washington. Snowstorms compiled from D.C. daily climate data obtained by author.)

The top 10 snow events in March in Washington range from 12 inches on the high end to 6.6 inches on the low end. The average snowfall of these events was 9.2 inches, with a median of 9.1 inches.

Only three of these top storms have happened since records have been kept at National. It happened most recently on March 9, 1999 when 8.4 inches of snow fell. The well known Superstorm of 1993 barely makes the list, though numbers were significantly higher to the west (as may be the case with Snowquester).

When it comes to the the kings of March for snow totals, the top 10 years range from 19.3 inches to 10.9 inches. The average for those seasons is 13.5 inches, with a median of 11.4 inches. Only one top 10 March snowfall has happened at National.

In a recent post about the 2” snowfall drought (now at 768 days) that we (fingers crossed) appear to be on our way to break, I noted that about one winter storm warning event (defined here as 5 inches or more snow) could be expected per winter in D.C., on average.


“Warning event” snows in D.C. One metric for a winter storm warning is 5 inches of snow. The graph is a count of those storms by season. (Ian Livingston)

Of course, once you’re at this point in the season, those “historical odds” are much worse: a measly 10 percent based the current climatological (1981-2010) odds

Combining March and April to cover the rest of the snow season, there have been 20 such events in 17 seasons (out of the 125 full seasons noted above). Since 1944, which includes the entire period of National measurements, there have been only five storms which produced five or more inches in D.C., all of which came in March.


Seasons which had the majority of their snow in March. Given that we stand at 1.5 inches as of publish, it seems quite likely we’ll add 2012-13 to the list going forward. (author modification of NWS Baltimore/Washington data)
Again using the climatological period of 1981-2010, and focusing on March through the end of the cold season, 1999 leads the pack with 8.7 inches of snow. 1993 brought 6.6 inches, 2009 had 5.5 inches, 1996 finished with 5.2 inches and 1995 recorded 4 inches.

Interestingly, the recent winters of 1998-99 and 2008-09 were not too much different than this winter leading up to their “big finales.” Both featured well below average snowfall (2.9 inches and 2 inches respectively) heading into the month.

Ultimately, 75 percent of the winter snowfall for 98-99 came in March 1999 and 73 percent of the winter snowfall in 2008-09 came in March 2009.

Of additional possible interest in our current situation, the biggest one day March snowfall of 11.5 inches back in 1942 came after a season with only 2.1 inches of snow before the storm. So, there is indeed some precedent for a jolting turnaround right at the end.

Related

Can D.C. dream the impossible dream of breaking the snow drought this winter?

What’s the weather like in D.C. in March?

Is April snow in D.C. becoming more rare?

When is the average last date of measurable snow in Washington, D.C.?

Does the “less snow, more blizzards” global warming theory hold up in Washington, D.C.?

By  |  09:07 AM ET, 03/04/2013

Categories:  Latest, Local Climate

 
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