Flooding in Delaware
On this page you learn what types of flooding are typical in Delaware and how do you protect yourself, your family and your home. You will also find out more about significant Delaware floods. Finally, you'll find links to NWS offices that provide forecast and safety information for Delaware, as well as links to our partners who play a significant role in keeping you safe.
|Significant Delaware Floods
Ash Wednesday Storm 1962
Ash Wednesday Storm 1962
Name of Flood: Coastal Delaware
Set Up: The March 1962 storm is the storm of many names. It’s known as “The Great Atlantic Storm” as well as the “Five High Storm” because it lingered off the Atlantic Coast over a period of five high tides. But because the heaviest damages occurred in most areas on Wednesday, March 7, which was the Christian holiday of Ash Wednesday, it’s become the "Ash Wednesday Storm of 1962."
The massive storm was caused by merging low pressure systems along the eastern seaboard with a strong surface high to the north. This caused the storm to slow and eventually stall in the mid-Atlantic for almost 3 days, pounding coastal Delaware with continuous rain, high winds, and tidal surges. To make matters worse, the storm occurred at the spring equinox, which created higher tides compared to normal.
Location Impacted: With a long ocean fetch, steady winds of gale force blew from the northeast. Gusts reached 70 mph resulting in storm tides of three to five feet above normal.
Waves more than 40 feet high occurred off of Rehoboth Beach. Waves in the Rehoboth Beach surf zone reached 20 to 30 feet destroying the boardwalk and beachfront homes.
The 1962 storm was the most destructive storm in Bethany Beach's history. The nor'easter arrived on the evening of March 5 with 80-mile-per-hour winds. Destruction was widespread throughout Bethany Beach. Many of the beachfront structures were destroyed, including the bowling alley, many inns and houses, the boardwalk, and the town pavilion. Flood waters penetrated as far inland as Ocean View. Extensive beach erosion occurred, and sand over three feet deep buried streets and cars and filled entire rooms in some houses.
At Dewey Beach, the ocean had breached the dunes, and the storm water cascaded through the resort to Rehoboth Bay. At Fenwick Island, the waves washed over the barrier island and continued into the coastal bay. For a time, an inlet developed just north of town. Many beach cottages were destroyed. Nearly every structure in the resort sustained some damage. The sea had spewed so much sand inland that the northbound lanes of the highway between Fenwick and Bethany were covered.
Number of Fatalities: 7
Dollar Damage: More than $70 million or around $500 million in 2013 dollars.
The Gale of 1878
Name of Flood: Coastal Delaware and Northern New Castle County
Set Up: On October 24, the “Gale of 1878” brought hurricane-force winds to the entire state of Delaware. It is one of only three storms to bring hurricane-force winds to the state. As the storm first moved north across North Carolina, the storm ran into a coastal front which enhanced rainfall well ahead of the storm.
Location Impacted: Winds and rain associated with the storm damaged or destroyed many houses statewide. The storm dropped over 3 inches of rainfall across the northern part of the state, flooding portions of Wilmington. Crop damage was severe. Telegraph lines failed. The Christina and Brandywine Rivers flooded. Much of Wilmington flooded. Flood waters reached into the first floors of homes and businesses. The Knowles’ wool mill in New Castle burned to the ground. A washout in Shellpot delayed trains on the P., W., and B. railroad north of Wilmington.
In Middletown, the Presbyterian Church, Episcopal Church, and the Delmarva Drying House were all damaged. The bridge over the St. Augustine creek and surrounding marsh was destroyed. In Dover, new carriages were destroyed. Everything at the fairgrounds was in ruin. Four drowned in Leipsic.
The strong winds sunk four ships, killing 14. A seven foot storm surge in Lewes drowned four. Beach erosion was severe. A large number of vessels were driven ashore. Government owned buoys floated inland. The schooner J. Dever capsized on the Christiana. Odessa saw many of its barns destroyed. Cattle perished. Several vessels were driven ashore.
At Lewes, a seven foot storm surge was measured at the beach. At Rehoboth, the beach eroded away. The railroad track bed at Maull's Glades was washed away. All bathhouses along the beach were destroyed.
Mispillion Light lost all of its stock when the tide swept it away from the base of the lighthouse. Cattle, horses, corn, and hay all were all lost due to the swollen waters on Mispillion Creek.
Number of Fatalities: 18
Dollar Damage: $45,000 or around $1 million in 2013 dollars.
Great Atlantic Hurricane 1944
Name of Flood: Coastal Delaware.
Set Up: “The Great Atlantic Hurricane” was a large storm which hit North Carolina on September 12th, reentered the Atlantic, and hit Long Island on the 15th as a Category 2 hurricane. It passed 50 miles to the east of the Delaware coast on the 14th. This was a historic storm, in the sense that, it was the first time aircraft reconnaissance was intentionally used to monitor a tropical cyclone.
Location Impacted: Rainfall totals were in the four to six inch range across the state.
Hurricane force winds were recorded along the entire Delaware coast. The freighter Thomas Tracy was grounded in Rehoboth Beach. The roof of the Rehoboth Beach city hall was lost. Gravel streets were washed out and sand was carried away from the beaches. In Bethany and Fenwick Island, every building was damaged or destroyed by winds and the tidal surge. A half-mile stretch of boardwalk at Bethany Beach was destroyed. The Ringler Theater was destroyed along with a large number of summer homes and year-round residences. The Ocean Highway between Bethany beach and Rehoboth was washed out due to the waves and surge. The lobby of the Hotel Henlopen was flooded. High water also caused damage along the Delaware Bay communities of Bowers Beach, Woodland Beach, Big Stone Beach, Kitts Hummock, and Slaughter Beach.
The combination of rain and tides caused the worst known flooding in Delaware City.
Number of Fatalities: None
Dollar Damage: Close to $500,000 in 1944 or around $6 million in 2013.
Remnants of Tropical Storm Henri 2003
Name of Flood: Red Clay River Basin, Northern New Castle County
Set Up: On Monday, September 15, 2003, the remnants of Tropical Storm Henri caused historic flooding in the Red Clay Creek watershed in Delaware.
Location Impacted: More than 10 inches of rain fell in a five hour period in the upper Red Clay drainage, exceeding the 24-hour 100-year return period value of eight inches for the area. The recorded peak discharge flood flow at the USGS Red Clay at Wooddale Gage, generated in a relatively small drainage area of 47 square miles, exceeded 32,000 cubic feet per second (cfs), the highest peak discharge on record dating back to 1943. The next highest peak flow of 7650 cfs occurred during Hurricane Floyd on September 16, 1999. Flooding was defined as a 1 in 500 year event. The flooding damaged hundreds of homes, including 194 in the Glenville area. The rapid flooding trapped numerous people in their cars and homes, forcing at least one rescue by helicopter. Those people were evacuated to nearby schools. Bridges were destroyed including one in Hockessin. Six Wilmington & Western Railroad bridges were also damaged or destroyed.
Number of Fatalities: None
Dollar Damage: $16.1 million in 2003 or around $20 million in 2013.
Hurricane Floyd 1999
Name of Flood: Christina River Basin, Northern New Castle County
Set Up: On September 16, Hurricane Floyd'seye tracked over Fenwick Island in extreme southeastern Delaware. A state calendar-day rainfall record of 10.58 inches was set at Greenwood, Sussex County. As the storm crossed over the southern end of the Delmarva Peninsula, the heaviest rainfall was on the northwestern side of the storm, where it collided with a stationary front.
The heavy rainfall associated with Hurricane Floyd began early on September 16, 1999, and continued late into the night. The amount of rainfall was highly variable over the region; some areas received more than 10 inches of rain while other areas received only five inches or less.
Location Impacted: Record floods reached 100-year discharges on many streams, and floods on several streams reached a 500-year discharge. Specifically, peak flows on White Clay Creek in New Castle County exceeded the calculated 500-year recurrence interval and both the Christina River and Red Clay Creek in New Castle County, Delaware, exceeded 100-year recurrence intervals.
Record flooding was confined mainly to the Christina River Basin in northern New Castle County, where most gaged streams reached record levels and discharges. The Christina River Basin, the largest river basin in New Castle County, includes the drainage areas of White Clay Creek, Red Clay Creek, and Brandywine Creek. Discharges during the storm of September 16, 1999, reached peaks up to and exceeding the calculated 500-year recurrence intervals. Peak flows in the Christina River, White Clay Creek, and Red Clay Creek exceeded the highest levels previously recorded for the periods of record at these stations. The winds and rain, associated with Floyd, affected many. Over 200,000 customers were without power at some point.
Number of Fatalities: 2
Dollar Damage: $8.37 million in 1999 or around $11 million in 2013.
Flash flooding is a rapid and extreme flow of high water into a normally dry area, or a rapid water level rise in a stream or creek above a predetermined flood level, beginning within 6 hours of the causative event (i.e., intense rainfall, dam failure, ice jam). More information...
River flooding occurs when river levels rise and overflow their banks or the edges of their main channel and inundate areas that are normally dry. More information...
Tropical Systems and Coastal Flooding
Wildfires burn away the vegetation of an area, leaving behind bare ground that tends to repel water. When rain falls, it runs off a burn scar towards a low lying area, sometimes carrying branches, soil and other debris along with it. Without vegetation to hold the soil in place, flooding can produce mud and debris flows. More information...
A back-up of water into surrounding areas can occur when a river or stream is blocked by a build-up of ice or other debris. Debris Jam: A back-up of water into surrounding areas can occur when a river or stream is blocked by a build-up of debris. More information...
Flooding due to snowmelt most often occurs in the spring when rapidly warming temperatures quickly melt the snow. The water runs off the already saturated ground into nearby streams and rivers, causing them to rapidly rise and, in some cases, overflow their banks.More information...
Dam Breaks/Levee Failure
A break or failure can occur with little to no warning. Most often they are caused by water overtopping the structure, excessive seepage through the surrounding ground, or a structural failure. More information...
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