Exactly how big was the East Coast blizzard?

Tallying storm totals is an imperfect science that still relies on rulers. But some meteorologists take human impact into account when comparing top blizzards. 

Cliff Owen/ AP
A man in Alexandria, Virginia walks his dog during snowstorms in this January 23 photo. Blizzards along the East Coast blanketed some areas in more than 3 feet of snow.

How big was Jonas?

After snowstorms calmed on Saturday night, East Coast Americans were curious whether the 1,000-mile blizzard had lived up to its hype. 

But figuring out where Jonas falls in the history books depends on snow measurements, an imperfect science still basically done with plywood boards and measuring sticks. On Saturday, the Washington Post reported that weather observers at Reagan National Airport had not followed proper protocol, possibly robbing the storm of a top three DC-area record. 

As of Saturday at 8:00 PM, Reagan reported 17.8 inches, which would give the storm a fourth-place tie with 2010's "Snowmageddon." But nearby Washington Dulles Airport reported 28.3, and urban corridor neighbor Baltimore got 29.2, the city's all-time record.

The problem at Reagan? Snow boards, according to the Post.

That's two words, not a reference to something you'd ride down a slope. The National Weather Service's 14-page guidebook on how to measure solid precipitation require observers to periodically measure snowfall against upright boards placed out of the way of drifts, trees, and buildings. The board must be wiped clean between each measurement, which typically takes place every six hours, and several different boards are measured to take an average. The periodic averages are totaled at the end of a storm.

But that's just snow count 101. The Weather Service actually takes four measurements: fresh snowfall; snow depth, a total count including ice; snowfall water content; and snowdepth water content.

Measuring on grassy areas is discouraged, since there may be an air gap between ground and snow, and icy layers can also present difficulties. In that case, the guide recommends "creativity" and "protective gear," particularly for observers attempting to saw through the ice.

But Reagan's measurements weren't done with snow boards, according to the Post. Part of the problem: if snow isn't measured periodically, using a freshly-wiped snow board, the weight of accumulated snow will compact it, producing a lower-than-accurate snowfall measure.

To earn a #1 spot in DC history, the blizzard would need to beat the "Knickerbocker," which dropped 28.2 inches in 1922. In other cities, however, its legacy was secure: the second-highest in New York's Central Park since 1869, for instance, at 26.8 inches, just one tenth of an inch short of the 2006 record. 30.5 inches were measured nearby, at Kennedy International Airport. Meanwhile, up to 40 inches were recorded in parts of Maryland and West Virginia. 

DC may need to wait for an official measurement to see where Jonas falls in the list of biggest-ever blizzards. In the meantime, Washington residents have been amusing themselves with the Post's snowstorm naming contest, although the paper overrode the people's choice — Make Winter Great Again, à la Donald Trump's campaign pledge — in favor of #Snowzilla.

The name "Jonas" was bestowed by the Weather Channel, which has adopted a policy of naming all significant snowstorms, typically inspired by mythology: since announcing the first in 2012, they've worked their way through Astro, Hercules, and Pandora, for instance. The Weather Channel claimed common names would improve safety; but some meteorologists say the opposite.

The hoopla, and genuine danger, presented by giant snowstorms isn't determined just by inches, though. The National Weather Service has created a Northeast Snowfall Impact Scale, or NESIS, which takes human impact into account and assigns blizzards a rating, from Extreme to merely Notable. Record-setting snowfalls on the East Coast are typically lower than in Western States, but because of transportation hubs, Atlantic storms' effects are often felt nationwide. 

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