DANVILLE— Route 11 is expected to be closed the rest of this week after a rock slide early Monday morning covered all four lanes of the road near the Montour-Northumberland County line.
The massive rock slide that left 7,500 tons of rock on Route 11, has halted traffic between the intersection with Route 54 in Danville to Ridge Road in Point Township. It was "triggered by heavy rainfall on Sunday night," said Pennsylvania Department of Transportation engineer Lloyd E. Ayres, on Monday afternoon.
The rock slide is approximately 2.2 miles west of Danville, Ayres said.
A detour using Route 147, Route 642 and Route 54 is in place.
As of late Monday afternoon, added PennDOT spokeswoman Maggie Baker, "we will have the detour in place through the end of the week. We will know more as we continue to work on it."
At a late afternoon meeting among PennDOT engineers and administrators, Ayres explained that "plans are currently being developed to remove the rock from the roadway so that repairs to the roadway can be accessed."
Whether there is any damage to the roadway from the rockslide will be determined once the rock is removed, Ayres said. He could not comment prematurely on how long it would take to fix the road if there is damage.
At this time, Ayres added, "we are estimating that approximately 7,500 tons of rock will need to be broken up and removed from the site."
Asked where will the rock be taken, Ayres said, "A waste site has not been determined yet."
"To the best of our knowledge," he said, "there are no motorists or vehicles under the rockslide."
"Our biggest headache was people trying to go down the road that was closed," Danville Police Chief Jonathan Swank said.
Police did not have to issue any citations, though, Swank said.
Though the highways are closed from Continental Boulevard (Route 54) in the borough, it is open to local traffic going to the middle school, businesses in that area and Bald Top Road, according to the chief.
Meanwhile, because traffic to the Danville Middle School would be impacted by the rockslide, Superintendent Ricki Boyle said she was notified by Columbia-Montour 911 at about 3 a.m. Monday morning about the road closure. "
At this time, Boyle said on Monday, there are workers at the intersection who have allowed those coming to the middle school to pass through.
"All staff and students made it to the building on time, on Monday," she said.
Rockslides at the site before
The current rock slide is southwest of the May 2019 rock slide on Route 11, Ayres said.
"It is nearby," he added.
Ayres noted that "this area of State Route 11 has a very high and steep rock cut located along the roadway. The slides have occurred due to the bedding angle of the rock and the continual weathering of the rock.
The rock composition is red shale and siltstone.
"High-intensity rain storms accelerate the weathering of the rock through the water runoff eroding the rock," he explained, cautioning, "If this is an embankment failure that is more than the rock slide that occurred last evening."
There has been a lot of road construction on Bald Top, but Ayres does not believe it was a contributing factor to the Monday landslide.
Ayres has seen several rock slides in this area — in 2019.
"The mitigation for major rock slides on existing roadways will normally include a larger scale project that includes excavating the rock slopes to a more stable slope, providing more room at the base of the slope for a catchment ditch, may include the placement of concrete barrier or engineered protective fence or the installation of other systems to anchor the rock or control the decent of the rock," said Ayres.