A southbound lane of Route 28 is closed between the Hulton Bridge in Oakmont and Powers Run Road in O’Hara following a rock slide Tuesday evening.

The closure went into effect around 10:30 p.m. Tuesday. It remained in place Wednesday morning, causing traffic backups to the Harmar exit, roughly a mile northeast of the bridge.

The lane will reopen once geotechnical engineers determine no other rocks will fall from the hillside, according to PennDOT spokesman Steve Cowan. There’s no timeline for how long that will take, he said.

Tuesday’s rock slide appears to have happened in the same vicinity where a similar rock slide happened in 2020.

The incident comes as the region warms up from a weekslong deep freeze.

“With temperatures changing from subzero to 50 degrees with significant snowmelt, I wouldn’t be surprised if we saw other slide issues within the region,” Cowan said.

Cowan noted that certain sections of Route 28 have long been susceptible to rock falls. PennDOT has protective measures in place to prevent this, including major work in 2008 to add heavy chain-link fencing, catch basins and reinforced concrete in a portion of the roadway.

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