With only 3.1 inches of snow to date this winter, snow lovers in and around Washington are getting restless. A weather pattern that is not providing much in the way of opportunity during this time of year is just making it harder.
Astute snow watchers will point out that February is marginally our snowiest month, despite fewer days and warmer temperatures, compared with January. At Reagan National Airport, the average snowfall is 5.7 inches in February vs. 5.6 in January. At Dulles, it’s 7.6 inches in February vs. 7.3 inches in January.
The first weeks of February are often touted as prime time for snow, for good reason. Chris Dolce and Jonathan Erdman of weather.com showed blockbuster snowstorms hammering the Northeast more frequently in early February than any other time.
We don’t have to look far back for big snows in this time frame around Washington, as the eight-year anniversary of Snowmageddon just days ago reminds us. More recently, there was the snowstorm of February 2014, dubbed Snochi by the readers of this blog.
Both in the long and short term, roughly the last 10 days of January and the first 20 of February make up our snowiest month, that is if we were allowed to define a month based on the snowiest 30-day period. Washington can get big events on either side of that period, but this is where the bulk of the big ones and a large number of more regular ones tend to occur.
The histograms of daily accumulated snowfall (shown above) reach their respective peaks during that final third of January into the first two thirds of February, more or less. Overall, the curve is weighted heavier to the right than to the left signifying the second part of winter is typically more snowy in Washington. There is even a perceptible bulge of healthier snow numbers that extend into the first third of March.
If we add up the total amount of snow that has accumulated every calendar day on record (back to 1888), we find a handful of dates that rise above the rest. While many are influenced by one or two large storms, there is no question that some days see more snow than others. Half have occurred in the first two weeks of February.
When you add up all the years, D.C.’s snowiest day in history is Jan. 28. Since 1888, 70.7 inches of snow have fallen on that day of the year. A record 21 inches that fell on that day in 1922, which led to the Knickerbocker Theatre disaster, really elevated it to the top
Next up is Feb. 7, with 52.8 inches.
The most recent 30-year period shows more variation in the snowiest calendar days because big storms carry more weight over shorter time frames. But over the long haul, every one of the 10 snowiest days in D.C. history occurred in that late January to mid-February period.
You see the same general story when examining the livelihoods of different snow amounts by week. They reveal that snowfall of various intensities favor the end of January and early February in particular.
From the week of Jan. 22-28 through the week of Feb. 5-11, Washington has at least a 50 percent chance of some measurable snow. If you’re only looking for a trace of snow, the weeks of Jan. 8-14 through Feb 12-18 all score a 70 percent chance or greater. That’s a pretty strong likelihood of at least flakes flying, and around here that’s not a bad bar for which to aim. . . .
Odds are never fantastic for a lot of snow in Washington, even over a week-long period. But to go through the period we are in now without any accumulating snow is something of an oddity. We’ve still got some time. Also, remember that in several recent years we’ve seen a disproportionate amount of winter snowfall during March.