Flash Flood — Mckean, Pennsylvania

2021-07-17 · near Port Allegany, Mckean, Pennsylvania

Event narrative

Flash flooding of several roads in the Port Allegheny area. A building collapse was also reported from a wash out.

Wider weather episode

Scattered showers and thunderstorms develop during the early afternoon hours of July 17, 2021 across western Pennsylvania and in the Lower Susquehanna Valley in an anomalously humid airmass ahead of an approaching cold front. The storms over the Lower Susquehanna Valley developed on a weak boundary in a high CAPE environment, and produced sporadic wind damage before moving to the east. The storms over western Pennsylvania eventually congealed into a broken line that progressed eastward across central Pennsylvania and had imbedded regions of damaging winds and very heavy rain. One hail report was received from beneath a particularly tall cell that developed over Blue Mountain just west of Marysville in Perry County. Flash flooding from these storms was reported across McKean, Dauphin and Tioga Counties.

View location on OpenStreetMap → (41.8229, -78.3058)

Source: NOAA Storm Events Database, event_id 971594. Narrative written by the NWS forecast office that issued the report.