Two of the Three Largest, Heaviest Northeast Snowstorms Since 1956 Have Happened in March

Two of the three most expansive, heaviest Northeast snowstorms since the mid-1950s happened in March, rather than the core winter months of December, January or February.

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From 1956-2017, only three of 34 Northeast snowstorms attaining a Category 3 or higher rating on the Northeast Snowfall Impact Scale (NESIS), have occurred in March, according to NOAA's National Centers for Environmental Information.

This NESIS scale, developed in 2004 by Paul Kocin, a National Weather Service meteorologist, and Dr. Louis Uccellini, the director of the National Weather Service, attempts to rank the impact of Northeast snowstorms based on snowfall amounts and the population affected.

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In general, widespread heavy snowfall over highly populated areas produces a high NESIS value for a given storm. Neither NESIS, nor its regional version, the regional snowfall index (RSI), factor winds or time of day/day of the week in its assessment of impact.

That lone pair of March Northeast "major" snowstorms, however, makes up two of the three highest NESIS scale ratings in the entire list dating to 1956.

The clear front-runner is the infamous superstorm of March 12-14, 1993, which deposited a massive swath of 10 inches or more of snow from Alabama to Maine, among other jaw-dropping impacts.

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The early March 1960 storm wasn't nearly as expansive but did bury areas from western North Carolina to New England in at least 10 inches of snow, crushing the northern suburbs of the New York Tri-State and eastern New England with over 20 inches of snow.

Despite producing blizzard conditions in parts of the Appalachians, with up to 42 inches of snow, the infamous Ash Wednesday 1962 storm will forever be remembered as the most extreme nor'easter on record for the Mid-Atlantic states, based on its coastal damage. 

Twenty years ago, an April Fool's snowstorm hammered New England, dumping 25.4 inches of snow in Boston in just 24 hours. However, that storm wasn't expansive enough to rank high on the NESIS scale, ranking only 47th as of this column.

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Perhaps the most crippling of all snowstorms to affect New York City also happened in March, which occurred before the underground subway system was built and well before the advent of snowplows.

The blizzard of 1888 hammered parts of New York, Connecticut and New Jersey with 40-50 inches of snow, with drifts over the tops of some homes. Travel was paralyzed for days. Four hundred people were killed either in the storm or in the cold aftermath.

As of this writing, 130 years later, the blizzard of 1888 remains among the top recorded snowstorms at New York's Central Park, one of only four March snowstorms to produce a foot or more of snow a the park in almost 150 years of records.

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The March jet stream is still powerful, owing to the temperature difference between more southern and northern latitudes.

With lingering arctic air plunging out of Canada increasingly mingling with warm, moist air from the Gulf of Mexico, the stage is occasionally set for powerful snowstorms tracking up the East Coast.

Jonathan Erdman is a senior meteorologist at weather.com and has been an incurable weather geek since a tornado narrowly missed his childhood home in Wisconsin at age 7. Follow him on Facebook and Twitter.