This most up-to-date drop in Washington’s snowfall will turn into official when the Nationwide Oceanic and Atmospheric Administration releases its new 30-year “climate normals” in May, its decadal replace of common climate circumstances for each location in america.
Whereas NOAA hasn’t finalized D.C.’s snowfall numbers, they’re simple sufficient to calculate. Beneath, we preview what they’re anticipated to point out and talk about their implications. (Notice, minor discrepancies between our numbers and NOAA’s closing numbers are doable because of variations in evaluation strategies.)
Shedding snow throughout a lot of the winter season
Inspecting how the latest 30-year averages have modified by month, our story of snow loss begins in November and ends in February. March is the one month that exhibits a rise when bringing within the new numbers from the previous decade (2011 to 2020).
New month-to-month snowfall averages for the District, primarily based on the interval 1991 to 2020, are beneath, with the previous interval (1981 to 2010) in parentheses:
- November: 0.1 inches (0.5 inches)
- December: 1.7 inches (2.4 inches)
- January: 5 inches (5.5 inches)
- February: 5 inches (5.7 inches)
- March: 2 inches (1.3 inches)
December and February confirmed the best snow loss, every shrinking 0.7 inches. Whereas January and February at the moment are technically tied for Washington’s snowiest months of the 12 months, February nonetheless has a slight edge when you think about it has fewer days.
A part of a long-term development
Contemplating Washington sometimes noticed about 20 inches of snow per winter round 1900, the town has misplaced a few third of its snowfall over the previous century or so.
Causes for long-term declines in snowfall are quite a few however are intently tied to the rising winter temperatures, which have eaten away at quantities, notably early and late within the season when it’s ceaselessly solely marginally chilly sufficient for snow.
Even for the reason that mid-Forties, when snowfall measurements moved from downtown Washington to Reagan Nationwide Airport, the common snowfall has fallen from about 18 inches to below 14 inches.
Snowfall declines additionally seen at Dulles and in Baltimore
The brand new averages present losses in snowfall at Dulles Worldwide Airport and Baltimore-Washington Worldwide Marshall Airport, as nicely.
At Dulles, each month (together with April!) besides March noticed declines. The seasonal common there fell from 22 inches to twenty.9 inches. Baltimore’s common fell 0.7 inches, from 20 inches to 19.3 inches, additionally exhibiting losses in all months however March.
Extra broadly within the Mid-Atlantic and Northeast, our evaluation of the info exhibits the lack of snow seems most pronounced in areas farthest south and at low elevations the place temperatures are ceaselessly solely marginally chilly sufficient to snow. In these areas, even small quantities of local weather warming decrease snowfall quantities, particularly in winter’s shoulder months.
As an illustration, tendencies in locations like Richmond and Norfolk are just like Washington. Solely midwinter tends to point out relative snowfall stability in latest a long time, whereas snow early and late within the season is vanishing.
To the north, these colder places might want to heat up some extra earlier than long-term warming turns into an issue for snow accumulation. In Philadelphia and Hartford, Conn., for instance, snow averages are up.
Is March the brand new winter?
As famous above, March is an exception in relation to Washington’s diminishing snow returns. Whereas all prior months confirmed a lower within the common, March numbers are up.
Washington’s March snowfall common is now about 2 inches, in contrast with 1.3 inches final averaging interval. At Dulles, it’s as much as 3.9 inches from 2.8 inches. And, in Baltimore, March snowfall climbed from 1.9 inches to 2.8 inches.
Whereas March does frequently embrace accumulating snow, the change right here is basically pushed by a number of latest snowy years like March 2014, when 12.7 inches fell in Washington.
As a result of March tends to supply much less in the best way of dependable snow than different winter months, it won’t take as a lot to maneuver the common, however our new March common continues to be the very best for the reason that 1951-1980 interval, when 2.9 inches was the expectation.
However taking a look at the long run, the story for March nonetheless resembles different months. March common snowfall has fallen from about 4 inches at first of the twentieth century to the two inches at present.
Traditionally, it turns into uncommon for accumulating snow to happen after round March 25 in Washington. Whereas it’s not exceptional to see flakes into early April, the clock is ticking louder by the minute.