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 the state fell during the period in the form of both rain and snow.    Snowfall across New Hampshire ranged from nothing along the immediate coast to 12 to 24 inches in Sullivan County and up to 24 to 48 inches in northern Grafton and southern Coos County.  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.
Total liquid-equivalent for the storm generally ranged from 4 to more than 6 inches in Rockingham and Strafford Counties, 3 to 6 inches across Carroll, Hillsborough, and Merrimack Counties, and 2 to 4 inches across Belknap, Cheshire, Sullivan and Grafton Counties, with lesser amounts in the Connecticut River Valley.  Precipitation amounts were highly variable across Coos County with values ranging from less than an inch in the Connecticut River Valley to more than 6 inches in the White Mountains.
Sustained winds and wind gusts were highly variable across the state with the strongest winds and gusts generally in the southern part of the state, but also dependent on elevation and exposure to east and northeast winds.  Based on observed reports, most areas in southeastern NH likely saw gusts in the 50 to 90 mph range.  The strongest gust reported was 94 mph at the Seabrook Nuclear Facility and a gust of 90 mph was recorded at the Isles of Shoals.  Across the state, wind gust reports were generally in the 45 to 65-mph range.   Official reported peak gusts included 94 mph at Seabrook, 68 mph at Portsmouth, 68 mph at Concord, 63 mph at Manchester, 49 mph at Laconia, 48 mph at Whitefield, 45 mph at Lebanon, 45 mph at Plymouth, and 44 mph at Jaffrey, 43 mph at Jaffrey, and 39 mph at Berlin.

Heavy Snow in SOUTHERN COOS, NEW HAMPSHIRE
From 23-FEB-10 23:00:00 to 24-FEB-10 15:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy Snow in NORTHERN CARROLL, NEW HAMPSHIRE
From 23-FEB-10 23:00:00 to 24-FEB-10 15:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy Snow in SOUTHERN GRAFTON, NEW HAMPSHIRE
From 23-FEB-10 23:00:00 to 24-FEB-10 15:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy Snow in SOUTHERN CARROLL, NEW HAMPSHIRE
From 23-FEB-10 23:00:00 to 24-FEB-10 15:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy Snow in SULLIVAN, NEW HAMPSHIRE
From 23-FEB-10 23:00:00 to 24-FEB-10 15:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy Snow in MERRIMACK, NEW HAMPSHIRE
From 23-FEB-10 23:00:00 to 24-FEB-10 15:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy Snow in NORTHERN GRAFTON, NEW HAMPSHIRE
From 24-FEB-10 17:00:00 to 26-FEB-10 09:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy Snow in SULLIVAN, NEW HAMPSHIRE
From 24-FEB-10 17:00:00 to 26-FEB-10 09:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy Snow in SOUTHERN GRAFTON, NEW HAMPSHIRE
From 24-FEB-10 17:00:00 to 26-FEB-10 09:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy Snow in NORTHERN CARROLL, NEW HAMPSHIRE
From 24-FEB-10 17:00:00 to 26-FEB-10 09:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy Snow in SOUTHERN COOS, NEW HAMPSHIRE
From 24-FEB-10 17:00:00 to 26-FEB-10 09:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter