May 13, 2011
A low pressure system and its associated warm front were slowly progressing through the Ohio valley bringing numerous rounds of showers and thunderstorms. Outflow boundaries left over from thunderstorms late on May 12th became a mechanism for re-development ahead and along the warm front on the 13th. Many of these storms were slow moving causing the flooding of many roadways in southwestern Pennsylvania and eastern Ohio.
Source: NOAA National Weather Service Storm Events Database (event 316753). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Westmoreland County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.