Flood — Delaware, Pennsylvania

2010-10-01 · near Chadds Ford, Delaware, Pennsylvania

Event narrative

Flooding along the Darby Creek in Darby Borough was described as the heaviest since Hurricane Floyd. Dozens of families were evacuated and sought shelter at the Mercy Fitzgerald Hospital. People were rescued from the second floor windows on Springfield Road. Water was six to seven feet deep at the intersection of Springfield Road and MacDade Boulevard. A few homes in the borough were severely flooded as well as one automobile parts store. Major flooding also occurred along the entire length of Chester Creek from Thornbury Township into Chester City. About sixty homes were damaged in Chester City. Upland and Brookhaven also had flooding along the Creek. There were about 100 county rescues from vehicles. One of the most harrowing occurred in Bethel Township where a vehicle was washed off a roadway and the female driver escaped the submerged vehicle through the passenger side window.

The Chester Creek in Chester had major flooding and its third highest crest on record. It was the highest crest since Hurricane Floyd in September of 1999. The creek was above its 8 foot flood stage from 120 a.m. EDT through 209 p.m. EDT on the 1st. It crested at 17.54 feet at 6 a.m. EDT. Crum Creek at Newtown Square had major flooding and its highest crest on record. The creek was above its 6 foot flood stage from 101 a.m. EDT through 947 a.m. EDT on the 1st. It crested at 13.06 feet at 445 a.m. EDT. The Main Stem of the Brandywine Creek at Chadds Ford had moderate flooding and was above its 9 foot flood stage from 247 a.m. EDT through 1120 p.m. EDT on the 1st. It crested at 12.94 feet at 145 p.m. EDT.

Event precipitation totals included 9.04 inches in Chadds Ford, 8.18 inches in Radnor and 7.00 inches in Drexel Hill.

Wider weather episode

A series of low pressure systems that moved north along a slowly moving cold front brought heavy rain into Eastern Pennsylvania on September 30th and October 1st. Event precipitation totals average 5 to 10 inches with the highest amounts in the Philadelphia western suburbs. Many streams and rivers flooded, but the worst flooding occurred in Delaware, Chester, Montgomery and Philadelphia Counties where waterways crested at moderate to major levels. For many gaged waterways, it was the worst flooding since June of 2006. Around Delaware County it was described as the worst flooding since Hurricane Floyd in 1999. The first round of heavy rain occurred during the early morning of September 30th, but extremely dry antecedent soil conditions were able to absorb most of the heavy rain and mainly just poor drainage flooding occurred. The second and heavier round of precipitation moved in during the evening of September 30th and continued into the morning of October 1st. The rain ended during the morning of October 1st.

A low pressure system formed along a stationary front off the Carolina Coast during the night of September 29th. At 8 a.m. EDT on September 30th, it moved into central North Carolina and continued to move north. The low slowly weakened as it moved north and reached Pennsylvania on the evening of September 30th. Another low pressure system formed off the Carolina coast during the late morning of September 30th. This low was able to ingest tropical moisture associated with dissipating Tropical Storm Nicole. At 8 p.m. EDT on the 30th, the low pressure system moved north into eastern North Carolina and at 2 a.m. EDT on October 1st, it moved into the Delmarva Peninsula. At 8 a.m. EDT on October 1st, the low pressure system was just east of Atlantic City on its way to passing through eastern Long Island during the afternoon of October 1st.

View location on OpenStreetMap → (39.8381, -75.6041)

Source: NOAA Storm Events Database, event_id 265685. Narrative written by the NWS forecast office that issued the report.