Landslide covers

Highway in debris

Stephen Knight

September 24, 2009

A substantial landslide covered a stretch of Mitkof Highway in mud, trees, rocks and other debris on Sunday night during a heavy and wind-whipped rainstorm. DOT Foreman Ted Sokol reported receiving a police call at about 6:30pm on Sunday evening concerning a mudslide across an area around the 6.2-mile point of Mitkof Highway. He and his four-man crew were assisted by PMPL and Petersburg police who were first on the scene.

In addition to the clearing of the highway itself, one primary concern was stabilizing a utility pole that had been pulled over by the slide. PMPL also provided emergency lighting for the DOT crew to operate under during very treacherous conditions of high winds, heavy rain and darkness. Sokol estimates he and his crew worked on the cleanup for a total of five hours, not wrapping up for the night until 11:30pm. Mitkof Highway remained blocked for close to two hours but was cleared of everything but a veneer of mud by the time the crews packed up for the night. Fortunately, no houses or vehicles were damaged nor were any injuries reported.

Sokol described the mudslide itself as being approximately seven feet tall and 125 feet wide and suggested it began about 1,000 feet up the hillside. “It went clear across Mitkof Highway to the pullout on the opposite side of the road,” he said. He estimated about a dozen or so trees were taken down in the slide, some of which measured as large as 30 feet in length and four feet in diameter.

After securing the utility poles, the next step was clearing the highway of debris, according to Sokol. “We pulled all the trees out,” he said. “And then we started baling out all the mud into the pullout area so we could reopen the lanes to traffic.” Finding the culvert heads on the side of the road where the landslide occurred proved a difficult task as the culvert heads were twisted and severely damaged by the sliding debris. But locating and clearing the culverts was essential as the water from the swollen creek was diverting onto the roadway itself. “We needed to get the water to drain properly,” he said. “The water was pretty much spreading across the road for a couple of hours Sunday night.”

Sokol indicated that the twin 48-inch culverts which run from the creek beneath the highway at that point usually do the job very effectively. “They can really hold a very high water volume,” he said. “But they can’t hold all the rocks and mud and the trees and branches and all the stuff that came down there Sunday night.” Sokol remains undaunted by the damage to the culverts, which will need to be cleaned out and repaired adding, “It’s nothing we can’t handle. We can clean up the area and get things put back together.”

Considering the massive amount of debris to be cleared, the highway was reopened quickly, though Sokol cautioned, “People just need to drive with caution out there, because there’s still a little bit of mud left on the road in that area.” Sokol had to chuckle when he pointed out that the area affected was part of the newly paved stretch of highway that ADOT had worked on all summer, having only completed their work about two or three weeks ago. “Fortunately, there was no damage to the road or the paintwork or the guard rails,” he said. “We’ll have to do some shoulder dress-up but that’s just part of the job when this kind of thing happens.”

When asked how commonly such massive mudslides occur out the road, Sokol replied, “It’s happened right in that area a couple of times. I think it probably happens about once every ten years or so.” As to what causes the situation, beyond the obvious heavy rainfall accumulation, he said, “I don’t know what the deal is up in the mountainside there. It must hold back a bunch of debris and once it gets the earth dam bulging behind it, it just blows it all down the hillside – and it seems to hit right in that same area.”

Aside from the work on the culverts and the removal of the massive debris pile in the pullout area across the road, the only other work remaining to be done is ditching work. Sokol went out of his way to point out that the police department was very helpful in controlling traffic in the area during the massive cleanup operation and that PMPL were equally helpful in getting them set up with lighting and other assistance. He estimates that all of the cleanup will be completed within a week. The rain, ironically, will clean off the remaining mud on the road surface.

Two additional, smaller mudslides occurred overnight on Monday and early Tuesday morning at the 5-mile and 19-mile points of Mitkof Highway. No injuries or damage to private property were reported and DOT crews were able to clean up both sites in a few hours.