Flash Flooding in Pennsylvania, March 21 to 22, 1999

Heavy rain affected all of the Lehigh Valley and Southeast Pennsylvania. This caused flooding along some of the major creeks and streams in eastern parts of the Lehigh Valley and throughout Southeast Pennsylvania. In addition the heavy rain caused the usual highway and poor drainage flooding throughout the region. The worst reported flooding was in Montgomery County. Flooding along the East Branch of the Perkiomen Creek caused road closures in both Salford and Franconia Townships. Farther downstream flooding along the Perkiomen Creek caused closures of Pennsylvania State Routes 29 and 73 in Perkiomen Township. Flooding along the Skippack Creek also caused road closures along Pennsylvania State Route 73 in Skippack Township. Heavy rain began during the late afternoon of the 21st and continued into the early morning of the 22nd. Storm totals exceeded two inches in many locations and this was too much rain to keep streams within bankfull. The heavy wet snow from the previous weekend left the ground in nearly saturated condition. No serious injury or property damage were reported.In Chester County, the East Branch of the Brandywine Creek at Downingtown reached its 7 foot flood stage at 2 a.m. EST on the 22nd, crested at 7.48 feet at 5 a.m. EST and was back within bankfull at 8 a.m. EST on the 22nd. The Valley Creek at Valley Forge crested just 0.03 feet below its estimated flood stage of 7 feet at 11 p.m. EST on the 21st.In Delaware County, the Crum Creek at Newtown Square crested above flood stage at 5.82 feet at 1 a.m. EST on the 22nd. Its estimated flood stage is 5.5 feet. The Chester Creek near Chester crested at 7.68 feet at 2 a.m. EST on the 22nd. Its flood stage though is 8 feet. In Philadelphia, the Frankford Creek at Castor Avenue crested at 5.33 feet at 1115 p.m. EST on the 21st. Its flood stage is estimated at 5 feet. The Wissahickon Creek within Fairmount Park (just before its confluence with the Schuylkill River) crested at 5.66 feet at 630 a.m. EST. Its flood stage is estimated at 5 feet. In Montgomery County, the Perkiomen Creek at Schwenksville crested at 8.33 feet at 630 a.m. EST on the 22nd. ITs flood stage is estimated at 7 feet. The Manatawny Creek at Pottstown crested at 4.54 feet at 815 a.m. EST on the 22nd. Its flood stage is estimated at 4.5 feet.In Bucks County, the Neshaminy Creek at Langhorne crested at 10.38 feet at 930 a.m. EST on the 22nd. It was above its 9 foot flood stage from 3 a.m. through noon EST on the 22nd. Storm totals included 2.83 inches in Wynnewood (Montgomery County), 2.55 inches in New Hope (Bucks County), 2.50 inches in Norristown (Montgomery County), 2.40 inches in Easton (Northampton County) and Sellersville (Bucks County), 2.34 inches at the Northeast Philadelphia Airport, 2.33 inches in West Chester (Chester County), 2.30 inches in Neshaminy Falls (Bucks County), 2.22 inches at the Willow Grove NAS (Montgomery County), 2.20 inches in Crum Creek (Delaware County), 2.09 inches in Perkasie (Bucks County), 2.02 inches at the Philadelphia International Airport, 2.00 inches in Green Lane (Montgomery County), 1.93 inches in Phoenixville (Chester County) and 1.77 inches in Glenmoore (Chester County) The low pressure system responsible for the heavy rain moved northeast from Atlanta, Georgia the morning of the 21st to Albany, New York the morning of the 22nd.