Flash Flood — Lehigh, Pennsylvania

2004-09-18 to 2004-09-19 · near Countywide, Lehigh, Pennsylvania

Wider weather episode

The remnants of Hurricane Ivan interacting with a slowly moving cold front caused widespread very heavy rain to fall during the first half of the day on the 18th in Lehigh County. Storm totals average around 5 inches and caused widespread poor drainage, creek and river flooding throughout the county. Hardest hit were the city of Allentown, Lower Macungie and Macungie Townships. It was estimated that 85 homes, 31 businesses and five public buildings and structures were damaged. The preliminary damage estimate was five million dollars. The Lehigh River at Walnutport (Northampton County) was above its 8 foot flood stage from 904 a.m. EDT on the 18th through 102 a.m. EDT on the 19th. It crested at 12.32 feet at 245 p.m. EDT on the 18th. Farther downstream the Lehigh River in Bethlehem was above its 16 foot flood stage from 212 p.m. EDT through 1156 p.m. EDT on the 18th. It crested at 18.79 feet at 700 p.m. EDT. The Little Lehigh Creek within Little Lehigh Park was above its 6 foot flood stage from 721 a.m. EDT on the 18th through Midnight EDT on the 19th. It crested at 10.49 feet at 345 p.m. EDT on the 18th. Farther downstream, the Little Lehigh Creek at 10th Street within Allentown was above its 8 foot flood stage from 1040 a.m. EDT through 951 p.m. EDT on the 18th. It crested at 10.05 feet at 615 p.m. EDT. The Monocacy Creek at Bethlehem was above its 4.5 foot flood stage from 540 a.m. EDT on the 18th through 752 a.m. EDT on the 19th. It crested at 9.67 feet at 2 p.m. EDT on the 18th. Storm totals included 8.90 inches in Orefield, 7.25 inches in Bethlehem, 5.32 inches in Coopersburg and 4.82 inches at the Lehigh Valley International Airport.

Source: NOAA Storm Events Database, event_id 5426508. Narrative written by the NWS forecast office that issued the report.