10 Years Ago, Twin 'Snowmageddon' Snowstorms Paralyzed Washington D.C. and Mid-Atlantic

Ten years ago, back-to-back snowstorms buried the mid-Atlantic in feet of snow, paralyzing Washington D.C., Baltimore and Philadelphia, smashing monthly and seasonal records in an epic winter setup that was virtually a polar opposite from the current mundane winter season.

And for the first time, social media helped name this event that definitely lived up to the hype.

The first "Snowmageddon" or "Snowpocalypse" snowstorm, as it was dubbed in social media, dumped over 20 inches of snow in many areas from southern Pennsylvania, northeastern West Virginia and Maryland into northern Virginia, Delaware and southern New Jersey Feb. 5-6, 2010. Blizzard conditions were observed at Baltimore/Washington International Thurgood Marshall Airport and Patuxent River, Maryland.

This storm is still the heaviest snowstorm of record at Washington's Dulles Airport (32.4 inches), second-heaviest in Philadelphia (28.5 inches) and fifth-heaviest in Baltimore (25 inches). "Snowmageddon I" dumped 10 inches more snow at Dulles Airport in two days than their average for an entire year (21.9 inches).

As the region was struggling to dig out, the sequel arrived. Just three days later, another snowstorm pummeled the mid-Atlantic, dumping another 10-plus inches of snow from northern Virginia to New York City Feb. 9-10.

If these back-to-back storms were grouped together, they would've been been only the third Category 5 Northeast winter storm in records dating to 1956, NOAA's February 2010 report said.

(MORE: Ranking the Most Extreme U.S. Winter Storms)

February 2010 wasn't just the snowiest February – it was the snowiest single month on record in Baltimore (50 inches), Philadelphia (51.5 inches), Washington's Dulles Airport (46.1 inches) and Atlantic City, New Jersey (36.6 inches), among other locations.

Unsurprisingly, those same locations went on to smash all-time seasonal snowfall records in 2009-10. Philadelphia (78.7 inches) tallied three and a half times its average seasonal snowfall.

Where to Put All the Snow?

Even along the East Coast, accustomed to major snowstorms, this double whammy in less than a week was crippling.

States of emergency were declared in Delaware, the District of Columbia, Maryland, New Jersey, Pennsylvania, Virginia and West Virginia. Power was knocked out to hundreds of thousands. Emergency shelters were opened for those without heat, and travel across the region was crippled.

By Feb. 9, 25% of D.C. plows were out of service and road salt was being rationed, WTOP radio reported.

"We are in the midst of a natural disaster, and no part of the D.C. area's transportation system is functioning very well," wrote the Washington Post's Robert Thomson on Feb. 9.

Area roads were an obstacle course. Medians were "piled high with snow that occasionally spills into the left lane," Thomson wrote. Pedestrians were seen walking in the road because sidewalks were impassable.

Bus stops weren't an option, either.

"A prospective passenger would have to stand in the travel lane or stand atop a snow pile and hope for the best," Thomson wrote.

And that was before the second storm.

Roof collapses due to the weight of snow were reported at a Smithsonian warehouse in Suitland, Maryland; an aircraft hangar at Dulles Airport; and a Walmart in Stafford Township, New Jersey, among other locations.

Front-end loaders and dump trucks were brought in to move the massive piles of snow from parking lots and streets to vacant lots.

Given the impassable roads and power outages, federal government offices in the D.C. metro area were shut down for four and a half days, affecting about 230,000 employees.

After using empty parking lots, city parks and even the Pimlico Race Course, the city of Baltimore resorted to dumping excess snow in the Inner Harbor.

Sussex County, Delaware, emergency management put out a request for anyone with large equipment or tractors to help lead the way for emergency vehicles to respond on unplowed roads. Delaware Gov. Jack Markell banned all travel in the state, except for emergencies and those who lost power at home.

A Pattern Unlike This Winter

Beginning the previous December and continuing through February 2010, the trap door of arctic air was wide open into the eastern U.S – historically so, in fact.

The Arctic Oscillation (AO) is a measure of how open this arctic trap door is. The more negative the AO, the higher the pressure over the Arctic, the farther south the jet stream nosedives in the United States, and the more numerous and persistent cold outbreaks are in the eastern U.S.

The most negative AO of any month on record was registered in February 2010, with December 2009 in third place, according to NOAA records dating to 1950.

This pattern was turbocharged by an active southern branch, or subtropical jet stream, and persistent blocking high pressure near Greenland, also known as the negative phase of the North Atlantic Oscillation.

(MORE: 5 Extreme Winter Weather Patterns)

This winter, however, has been the opposite.

The Arctic Oscillation has been strongly positive since January, locking up the coldest air in the Arctic.

Instead of blocking high pressure near Greenland, the North Atlantic Oscillation has also been solidly positive, allowing most East Coast storms to scoot out to sea before intensifying.

Any winter storms that did approach from the central U.S. often have drawn up just enough warm air to keep precipitation more rain than snow in the mid-Atlantic this season.

Philadelphia has picked up only 0.3 inches of snow, its second-least-snowy season through Feb. 3. Only the 1972-73 season had less snow through Feb. 3 – no accumulation – in records dating to 1884.

Social Media's Weather Emergence

The twin February snowstorms marked the awakening of social media, changing how weather was covered.

The Twitter hashtags #snowpocalypse and #snowmageddon were used by many before, during and after the snowstorms.

Anyone with a Twitter account could search for tweets with those hashtags and see storm reports, photos of the mammoth snow piles and pictures from grocery stores jammed before the storm.

Keep February 2010 in mind if you long for snow in the mid-Atlantic. Perhaps an early spring isn't so bad.

The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.