Lably
Skip to content

February 5–6, 2010 North American blizzard

Weather event in North America

  • 17 min read
  • 7 chapters

Related on Lably

Through Interstate Highway System and Thunderstorm

Most crippling was the widespread 20 to 35 in (50 to 90 cm) of snow accumulated across southern Pennsylvania, the Eastern Panhandle of West Virginia, northern Virginia, Washington, D.C., Maryland, Delaware, and South Jersey, bringing air and interstate highway travel to a halt. Rail service south and west of Washington, D.C., was suspended, and rail travel between D.C. and Boston was available with limited service. Blizzard conditions were reported in a relatively small area of Maryland, but near-blizzard conditions occurred across much of the Mid-Atlantic region. The nor'easter reached a minimum central pressure of 976 mb while out at sea on February 7.

This event was the second of four nor'easters during the 2009–2010 winter that brought heavy snow to enough of the Northeast's population to be numerically recognized by NOAA's NESIS intensity rating. The first and third of these systems, the December 2009 Northeastern U.S. blizzard and the February 9–10, 2010 North American blizzard, respectively, combined with this event to bring the snowiest winter on record to much of the Mid-Atlantic. Additionally, this event was the second of three major Mid-Atlantic snowstorms that occurred over a 12-day period; each subsequent storm focused its heaviest snow slightly farther north: the January 30, 2010, storm (not recognized by NESIS) dropped more than a foot of snow across Virginia and the lower Chesapeake Bay region, while the February 9–10, 2010 North American blizzard bulls-eyed the Maryland-Pennsylvania border with as much as 38.3 inches.

Meteorological history

The main storm system originated in the Pacific Ocean, bringing heavy rain and mountain snow to California and Arizona on February 2. The storm center moved east through northern Mexico on February 3. The system produced over one foot of snowfall in the higher elevations and the eastern plains of New Mexico, shutting down major highways including Interstate 40 east of Albuquerque for several hours on February 3. The storm's center then advanced across Texas to the Louisiana Gulf Coast on February 4, while dropping rain and snow in Oklahoma and northern Texas, and severe thunderstorms further south. Meanwhile, a second, more-northern disturbance tracked from the central Rockies to the lower Missouri River Valley, bringing light snow showers to Montana, the Dakotas, parts of Minnesota, Wisconsin, Iowa, and Illinois.

On February 5, the two systems phased together, resulting in a band of heavy snow across Illinois, Indiana, Ohio, and Pennsylvania. That evening, the northern system's energy was absorbed into the main southern circulation, promoting fast intensification. Heavy snow subsequently developed over the Mid-Atlantic states as the storm's center tracked across North Carolina towards the Atlantic Coast.

An antecedent and nearly-stationary upper-level ridge over the Maritime Provinces of Canada served to block the storm system from following the traditional northeast track into New England. Instead, during the AM hours of February 6th, the storm center slowed its northeasterly movement as it continued to deepen east of Virginia Beach, before it eventually was forced eastward. The blocking pattern was reflected on the storm's snowfall map by a sharp northern gradient in northern New Jersey and by the axis of heaviest snow running WNW-ESE through Maryland and Delaware (opposed to the SW-NE pattern found from most nor'easters). Only moderate accumulations reached the southern suburbs of New York City, with no more than light snow falling in the city itself. Upstate New York and New England were spared from this system, receiving little more than isolated snow flurries in southern sections. Easterly winds and onshore flow contributed to light snow accumulations of less than one inch in Boston, Cape Cod, and parts of coastal Rhode Island.

According to the blog of Weather Channel senior meteorologist Stu Ostro, the storm formed from "Miller Type B" cyclogenesis: a storm centered over the Ohio river runs into a blocking ridge and redevelops along the Carolina coast. (This differed from the North American blizzard of 2009, of "Miller Type A" cyclogenesis where a storm center develops over the eastern Gulf of Mexico and strengthens while tracking north to a latitude of greater temperature contrast.) This storm was carrying an enormous amount of moisture drawn from both the Gulf of Mexico (as seen on February 3 satellite imagery over Mexico), and from the Atlantic (as seen in radar imagery from early on February 5). Ostro characterized the storm as having "strong dynamics" and expected the snowfall to be of long duration, typically leading to large accumulations.

Sign in to keep reading

6 more chapters are free with a Lably account.

More in Earth science