What is the ‘D.C. snow hole,’ and is it real? (2024)

A snow hole, or lack of snow compared with surrounding regions, forms near and to the west of D.C. in February 2021. Shown are snowfall totals (in inches) from Feb. 10-18, 2021. (National Weather Service)

Snow lovers have long lamented the dreaded “D.C. snow hole,” which refers to a relative lack of snow sometimes seen in or near the District, leaving a gaping hole in snow totals compared with surrounding regions. The supposed snow hole phenomenon has been blamed for embarrassingly low snow totals for individual storms and for entire winter seasons.

So, is the D.C. snow hole real or imaginary?

To answer the question, it’s helpful to first acknowledge there are two types of snow holes at play.

First, there is the microscale snow hole, which is the focused area of suppressed snow accumulation that often occurs in downtown D.C. and across the Potomac River in and around Arlington and Alexandria. That snow hole is absolutely real and a result of the combined impacts of low elevation, the urban heat island effect and proximity to the river.

Temperatures are almost always warmer at low elevations closer to sea level than at higher altitudes, because air is heated from the ground up. Meanwhile, the pavement and buildings in urban areas retain more heat than the grassy and forested surfaces of more rural locations. In addition, the Potomac River helps keep nearby temperatures warmer because water is slower to cool than land.

The confluence of warming factors makes it harder for snow to stick, thus the microscale snow hole commonly seen inside and right around the District and reflected in Washington’s official snow totals, measured at Reagan National Airport in Arlington on the bank of the Potomac.

This microscale hole is especially evident during snow that doesn’t fall heavily enough to cool down the air near the ground and during some late-season March snows when the increasing sun angle keeps the ground warmer. It occurs often enough that Capital Weather Gang and others sometimes incorporate it in their snowfall forecast maps.

The existence of a broader D.C.-area snow hole is a bit fuzzier.

Over the long term, there is no such snow hole, as can be seen in the map of average annual snowfall below. The map shows gradually decreasing amounts of snow from the Northeast into the Mid-Atlantic, with no sign of a hole in the D.C. area.

(Northeast Regional Climate Center)

In some winters, however, we have seen a zone of less snow in and around the D.C. area — such as the glaring snow hole that stretched from Charlottesville to Baltimore in the winter of 2016-2017 — due to tendencies in the seasonal storm track. In these cases, a split flow in the atmosphere tends to steer disturbances either to our north or to our south, leaving us struggling for snow in between. The disturbances may end up merging off the coast before bringing significant snow to the Northeast or New England, but that’s often too late to produce substantial snow around here.

“Long-term data does not show more snow surrounding D.C. than in the District itself,” Capital Weather Gang’s Ian Livingston wrote in 2021. “However, there are some years … when weather patterns can conspire to favor a snow-hole type pattern.”

This type of broader snow hole was last seen when a stormy stretch from late January through mid-February 2021 produced noticeably less snow near and west of D.C. than in surrounding regions. Similar snow holes occurred in the winters of 2017-2018, 2016-2017, 2012-2013 and 2010-2011.

The split flow in the atmosphere that can result in a regional snow hole tends to be more common in La Niña winters. But the sample size isn’t big enough that we can make any concrete conclusions about what is currently a strong El Niño winter.

Only time will tell how much snow the region receives this winter — and whether there’s a hole in the middle of it.