A nor'easter caused sleet to fall across New Castle County from the morning and into the evening of the 16th and a wintry mix of freezing rain and sleet to fall in Kent County during the evening of the 16th. Heavy rain fell prior to the change to the wintry mix in Kent County.  The nor'easter caused numerous accidents, especially in New Castle County where over 100 accidents were reported. Accumulations averaged 1 to 3 inches in New Castle County and an inch or less in Kent County. Ice accretions averaged less than one tenth of an inch in Kent County.
Precipitation started as rain across the region during the evening of the 15th. But as colder air moved in aloft, precipitation changed to sleet during the morning of the 16th in New Castle County. As the low pressure system tracked closer to the state during the afternoon of the 16th, the change to sleet stopped in New Castle County. As the low moved farther offshore, and the winds backed more to the north, colder air filtered south into Kent County and changed precipitation over to sleet and freezing during the evening of the 16th. All precipitation ended across the area around 1 a.m. EDT on the 17th.
In New Castle County, one of the worst reported accidents occurred in the Red Lion area. Six people were injured, one seriously when two vehicles collided at Old Porter and Red Lion Roads. An evening crash forced the state police to close Southbound Delaware State Route 1 between Tybouts Corner and Wrangle Hill Road (Delaware State Route 72) for about two hours. Several area roadways became gridlocked as workers rushed home early. The city of Wilmington dismissed non-essential workers an hour early. The city also postponed the Saint Patrick's Day parade that was scheduled to occur the next day (Saturday the 17th).

Sleet accumulations included 3.0 inches in Hockessin, 2.9 inches in Pine Creek Valley and 2.4 inches at the New Castle County Airport. The wintry weather was caused by a nor'easter low pressure system that developed on a cold front that moved through the area on the 15th. Prior to that, unseasonably mild air helped push high temperatures as high as the 70s. A strong high pressure system moved across nearby Canada and supplied a fresh supply of cold air into the region. Meanwhile, the low pressure system formed over South Carolina and Georgia on the morning of the 16th and moved northeast. At 2 p.m. EDT on the 16th, it was near Myrtle Beach, South Carolina; at 8 p.m. EDT that evening, it was just east of Virginia Beach; at 2 a.m. EDT on the 17th, it was about 100 miles east of Atlantic City, New Jersey and was about 100 miles south of Cape Cod, Massachusetts at 8 a.m. EDT on the 17th. As central pressures go, this was not particularly a powerful system; it was only 996 millibars the morning of the 17th. What contributed to the event was the strong high pressure system (about 1040 millibars the morning of the 16th). It supplied the fresh cold air and increased the pressure gradient (and consequently the wind) between itself and the developing nor'easter low pressure system.

Winter Weather in NEW CASTLE, DELAWARE
From 16-MAR-07 10:00:00 to 17-MAR-07 00:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in KENT, DELAWARE
From 16-MAR-07 18:00:00 to 17-MAR-07 00:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter