Jul 4, 2011
Isolated severe thunderstorms developed in the afternoon as a cold front began to sag across the region on the 3rd. The weak front then stalled along the Mason-Dixon line. As an upper level short wave progressed across the front on July 4th, additional thunderstorms developed. Wind damage and flooding occurred in Pennsylvania, West Virginia and Maryland.
Source: NOAA National Weather Service Storm Events Database (event 333392). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Allegheny County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.