The National Weather Service said two EF0 tornadoes touched down in Derry Township, Westmoreland County, on Saturday just after 5 p.m. Matthew Kramer, a meteorologist with the agency, said the damage suggested both storms were weak, around 70 mph.
He said crews were still dealing with the aftermath on Monday, including road repairs and debris cleanup after flash flooding washed out part of Green Thumb Road and the Laughlin Farm Road Bridge over Story Run. Residents and crews in Derry Township were left dealing with both tornado damage and water damage from the same storm cells.
Matthew Kramer and the damage path
Kramer said the first tornado ran along Red Cut Lodge Road and the township border with Latrobe. The second was identified along Rod-Gun Road, Matson Road and Carey Lane near Derry's border with Ligonier Township. That second path gave the National Weather Service the on-the-ground evidence it needed to map a separate track rather than treat the damage as one long line.
“Both of them appear to have been on the weaker side, somewhere in the 70 mph range, based on the damage we are seeing,” Kramer told Chris DeRose. “But it was not a continuous track, and they appear to be two separate circulations. And if they are the same circulation, there was considerable weakening between them, so we call them two distinct tornadoes in the case.”
Westmoreland County and Jefferson County
Kramer said the Pittsburgh coverage area had 19 tornadoes before Saturday. He said the weekend storms could push the seasonal total above 22 or 23, with normal around six. A tornado also touched down in Jefferson County, adding another report to the same round of severe weather.
The National Weather Service said Tuesday's storms could produce more tornadoes, so the immediate practical step for residents is to stay weather aware while road and bridge repairs continue in Derry Township. For anyone traveling through the affected area, the unresolved issue is how much total damage the tornadoes and flooding caused across Derry Township and Jefferson County.
