Coastal Flood and High Wind in Delaware, November 11 to 14, 2009

A powerful nor'easter produced wind gusts nearly as high as 60 mph, widespread moderate tidal flooding, heavy rain and severe beach erosion along the Delaware coast from November 12th through the 14th. Preliminary damage was estimated at 45 million dollars. The highest winds occurred from the morning of the 12th into the afternoon of the 13th. About 13,000 people in Delaware and Maryland lost power. The heaviest rain fell on the 11th and 12th. The combination of heavy rain and tides caused about 50 roads in Delaware to be closed, the most notable Delaware State Route 1. Parts of the roadway remain closed through the 15th as three feet of sand accumulated on it. Service on the Cape May Lewes Ferry was limited. The highest tides occurred with the morning high tide on the 13th. This was the highest tides in Sussex County since the February 5, 1998 nor'easter. Because of the persistent onshore flow, tidal flooding also occurred in Rehoboth and Indian River Bays. Tidal departures reached four and a half feet.

Delaware Governor Jack A. Markell declared a state of emergency on the 12th. The National Guard was mobilized to help with possible evacuations. In Sussex County, many schools closed early on the 12th. Voluntary evacuations occurred in Oak Orchard, Riverdale and Mariners Cove. The Community Church in Oak Orchard was used as a shelter by about 100 people. Water rescues were performed on Delaware State Route 1, Long Neck Road and Cannon Street.

In Lewes, several roads were flooded and closed including Savannah Road. In Rehoboth Beach, half of the dune sand was gone. There was a cut in the dunes north of the Henlopen Hotel. In Dewey Beach, flooding occurred along Rehoboth Bay. In Indian Beach, the dunes broke in several places and waves broke under homes. Within the Delaware Seashore State Park, there were several dune breaks. One break flooded Delaware State Route 1 with water and sand just north of the Indian River Inlet Bridge. The roadway remained closed through the 15th. Beach erosion was described as the heaviest in Indian Beach and within the Delaware Seashore State Park. In Oak Orchard, Indian River Bay flooding was ranked as the third worst since the 1962 Ash Wednesday nor'easter. In Bethany Beach, four dunes disappeared and flooding occurred in the north side of the municipality. Waves were measured at 10 feet along the shore. In South Bethany, no dunes were left along the south side of the town.| |Tidal flooding extended upward into Delaware Bay and along tidal sections of the Delaware River, but gradually became minor. The highest tide at Reedy Island in New Castle County was 7.35 feet above mean lower low water on the morning of the 14th. Minor tidal flooding begins at 7.20 feet above mean lower low water.

Peak wind gusts were all in Sussex County and included 60 mph in Fenwick Island, 56 mph in Lewes and Rehoboth Beach and 46 mph in Georgetown. The highest tide at Lewes reached 7.88 feet above mean lower low water on the morning of the 13th. Moderate tidal flooding ranges from 7.00 to 7.99 feet above mean lower low water. This was the highest tide recorded in Lewes since the February 5, 1998 nor'easter.

The nor'easter was originally Hurricane Ida, which made landfall in Alabama on the morning of the 10th. As Ida made landfall, it lost tropical characteristics and transformed into an extratropical low pressure system. On the morning of November 11th, the low pressure system reached southern Georgia and the next morning (12th) it was located over the coastal waters east of Wilmington, North Carolina. Of equal importance, was a high pressure system that moved across New England and the Canadian Maritimes from the 12th through the 14th. Its effects were threefold, it increased the difference in surface pressure (thus increased the winds), it blocked the low pressure system from moving offshore and provided a very long fetch of onshore flow. The extratropical low pressure system reached its maximum strength of around 995 millibars during the evening of the 12th as it was located just off of Cape Hatteras, North Carolina. From there, the low pressure system slowly drifted off the North Carolina coast as it slowly weakened on the 13th and 14th.