The National Weather Service in Pittsburgh issued a flash flood warning until 1:30 p.m. Thursday for northwestern Allegheny County and southeastern Beaver County.
Flooding was reported around Bell Acres, Leetsdale Borough and Leet Township.
Roads and highways, including Route 65, the Pennsylvania Turnpike and interstates 79 and 376, were affected.
PennDOT reported Thursday afternoon that southbound Route 65 at Quaker Village Drive in Leetsdale Borough, Route 4029 (McAleer Road) between Rochester Road and Mt. Nebo Road in Ohio Township and Franklin Park Borough, and Route 4022 (Mt. Nebo Road) under I-279 in Ohio Township were closed to traffic.
As of Friday morning, Fern Hollow Road in Sewickley Hills Borough was still closed to traffic, according to PennDOT.