Heavy Snow in Maine, February 24 to 26, 2010

A major storm system affected the northeastern U.S. from February 23rd through March 2nd. Areas of surface low pressure rotating around an upper level atmospheric system brought high winds, heavy snow, heavy rain, inland and coastal flooding, and coastal erosion to the area during the period.

On Monday, February 22nd, an upper level trough moved east from the Midwest. As the upper level system approached the East Coast on Tuesday, the 23rd, an area of surface low pressure developed off the North Carolina coast and moved northeast to east of the Delmarva Peninsula by the morning of the 24th. As this low moved northeast, a very strong and moist southeast flow developed between the low and a large area of high pressure over southeastern Canada. The initial surface low hooked to the west as it rotated around the upper level low pressure system and gradually weakened.

By the morning of the 25th, a second surface low developed off the east coast and rotated around the upper level system as it intensified rapidly during the day. Like the first surface low, the pressure gradient between high pressure over southeastern Canada and the intensifying low brought a continuation of the high winds, heavy rain, heavy snow, coastal flooding, and coastal erosion to the northeast. The high winds brought down trees and branches throughout the area and caused widespread power outages and blocked many roadways. In addition, flooding damaged and/or closed many roads. Along the coast, the strong east to northeast winds caused tides to surge which led to coastal flooding in the flood-prone areas. In addition, the strong winds generated large and powerful waves that battered coastal areas and caused coastal damage and erosion.

The upper level low pressure system remained over the northeastern U.S. through the morning of February 28, and then started to move slowly northeast. As it did, a third surface low developed well off the East Coast, moved north, but then rotated northwestward under the influence of the upper level system. This third low caused the strong northeast winds to continue across much of New England, especially along the coast where the winds continued to produce large waves, and coastal flooding and erosion with each high tide.

By the morning of March 2, the upper level system was located southeast of Nova Scotia and moving away from the region. Winds associated with the surface low gradually diminished during the day although tide levels remained high for several days.

Precipitation across Maine fell during the period in the form of both rain and snow. Snowfall across ranged from nothing along the coast to 24 inches in the mountains. Snowfall amounts were highly dependent on elevation and the higher elevations had significantly more snow than lower elevations which mixed with or changed to rain.

In terms of precipitation, most of the southwest coast and southwest interior zones received from 4 to 7 inches of rain with the mid-coast coastal and interior zones generally receiving 3 to 5 inches of precipitation. The foothills of Maine generally received from 2 to 4 inches of liquid-equivalent precipitation with the mountains generally receiving 2 to 3 inches of precipitation.

Sustained winds and wind gusts were highly variable across the state with the strongest winds and gusts generally in coastal areas, especially in the southwestern corner of the state. The winds and gusts were dependent on elevation and exposure to east and northeast winds. Based on observed reports, most areas in southwestern Maine likely saw gusts in the 40 to 80 mph range. The strongest (unofficial) gust reported was 94 mph at Cape Elizabeth. The strongest official wind gust was 78 mph at Portland, which was a new record for the site. Official reported peak gusts included 78 mph in Portland, 58 mph at Bar Harbor, 54 mph at Rockland, 52 mph at Wiscasset, 45 mph in Bangor, 43 mph at Lewiston, 40 mph at Augusta, and 31 mph at Fryeburg. The Sanford observing site reported a 52 mph gust before the site lost power.