The St. Patrick's Day snowstorm we just endured will go down in the record books as the biggest storm on that date in DC history. The previous St. Patrick's Day record was only 1.9" of snow. While this storm easily broke the record with 3.9" on the holiday itself, the real wallop was with the storm total. We got 7.2" of snow at Reagan National from Sunday night into Monday morning! This storm, plus the early-March snow and ice, bring us to a grand total of 11" for March 2014. This is the snowiest March on record since... can you believe it... 1960?!?! It's been half a century since DC has had this much snow, this late in the season!
"SnowPatricksDay", as it was dubbed, seems to be the last straw for many Washingtonians, even those who normally love the snow. Our seasonal snowfall total is now almost exactly double the 30-year average, at 30.3" (The average is 15.4"). However, this number is still not high enough to crack the top 10 snowiest winters in DC. So now the question is, will we get one or two more snowstorms that push us over the edge, and into the top 10?
While it is possible, of course, that we could get another big snow storm or two, it's highly unlikely. As of today, we are exactly nine inches short of creating a tie for the 10th-snowiest winter in DC (39.3" in 1910-1911). A snowfall of nine inches or more in DC has only happened twice this late in the season in recorded history (in 1942 and in 1891). And these storms were extreme outliers; on average, after March 17th, we only get 0.2" of additional snowfall for the entire season.
April is notoriously sparse for snow-lovers. The most recent April snow at Reagan National happened in 2007, but it was a paltry 0.4" of accumulation. Since 1888, there have only been nine April snowfalls of 1" or more, with the most recent one happening in 1924! Yep, that was quite awhile ago. We can only expect accumulating snowfall (more than a trace) at Reagan National about once every ten years. Add in trace snowfall events, and the number only increases to two out of every ten years. That means, most of the time, we do not see any snowflakes in the month of April in Washington. By stark contrast, DC gets accumulating snow nine out of every ten Marches, and we have never had a March in recorded history without at least a trace of snowfall in the month. So, the frequency of snow events rapidly declines from March to April, and so does the amount of snow in each event!
One last thing... a snowy March doesn't increase the odds of getting snow in April. Since 1888, there have been 24 Marches with at least 6" of snow. Only three of those Marches were followed by snow in April of more than a trace. Statistically, it means that there is no correlation. This winter has been surprising at every turn, though, so maybe we'll get one last surprise to finish out this sneakily snowy season!