Coastal Flood and Rip Current in Delaware, August 29 to 31, 1999

The combination of swells from Hurricane Dennis and a stiff northeast flow caused by a strong high pressure system building over New England produced rip currents and minor tidal flooding the last couple of days in August. Rip currents from Dennis started along the Delaware Beaches on Sunday August 29th. About 100 rescues occurred with a few minor injuries. On Monday the 30th swimming was banned at most of the Delaware Beaches. As Dennis pulled east of North Carolina on the 31st and weakened, the rip currents slowly ceased. Restricted swimming was permitted on the 31st. A major contributing factor to the winds and rip currents was a very strong high pressure system that built into eastern Canada and New England on the 30th and 31st. The northeast flow around it and Hurricane Dennis produced wind gusts up to 50 mph on the 30th and caused some minor tidal flooding from around Noon on the 30th into the afternoon of the 31st. Minor tidal flooding extended into the back bays and inlets as the northeast winds prevented the tide from receding. On the 30th, the waves and tide reach the dune lines and under the boardwalk at Rehoboth Beach. The water also reached the bulkhead at one end of Bethany Beach and caused flooding along Pennsylvania Avenue, a frequently flooded location. As both Dennis and the high pressure system weakened, tides subsided after the afternoon of the 31st. The constant pounding and strong winds did cause beach erosion. Ocean Drive in South Bethany was sand covered because of the strong winds. The highest tide at Lewes reached 6.6 feet above mean lower low water around 1 a.m. EDT on the 31st.