SMITHS FERRY, Idaho — There are some concerns about safety on Highway 55 near Smiths Ferry after the third rockslide in less than a year happened Saturday night. This incident is just a week before the McCall Winter Carnival, which could see thousands of cars on the busy road.
"The safety of the public is of the utmost concern to Idaho Transportation Department (ITD)," Vincent Trimboli, a spokesperson for ITD said. "Our mission is 'Your safety, your mobility, your economic opportunity.' But safety is first and foremost in that mission statement for a reason."
According to Trimboli, the cause of the rockslide was due to heavy snow and ice "putting a lot of weight on the hillside." He added crews were able to clean and clear the road and stabilize the hillside within hours after the rockslide happened.
However, because of recent history, Trimboli said a third-party, geotechnical expert was brought in to assess the area and slopes to check if things were safe before ITD opened the road to the public.
"This geotechnical expert helped us with the rockslide on Highway 95 a few years ago near Riggins and New Meadows," Trimboli said. "They came in and helped us decide the best ways to troubleshoot that rockslide. Essentially, we blasted that hill in a similar fashion to what we're doing here to make it safe for the traveling public."
The road on Highway 55 was reopened to the public Monday night.
Barry Miller, a Boise area project engineer and project geologist, said the first thing a geotechnical expert would do upon arriving on the scene of a rockslide would be to examine the area just above the incident. He said there could be some rocks, trees or other debris that could still fall and they would want to confirm nothing would fall on crews working.
Miller mentioned it would be hard to deem an area "safe," but engineers would want to look at the rock and see if it is "dipping or tilting towards the slide area." They would also examine to see if there is any water or snowmelt in the rock, because if that is the case, it could push rocks apart and slide down.
However, because this is the third time a rockslide in the area has happened in less than a year, there could still be questions.
"It would make you think there's something going on we don't fully understand," Miller said. "Maybe there are some different rock or soil conditions, maybe there's something we haven't discovered in our fieldwork that's causing this problem to occur, or maybe there is a weather event. There may just need to be more investigation."
Miller is not part of Highway 55, Smiths Ferry Project construction team, but he said he was able to take a tour of the construction site on Highway 55 over the summer.
"Everything they're doing seems to be in line with the standard practice," Miller said. "There are tricky materials and it's a steep area with really tight constraints and things happen."
While work with the Highway 55, Smiths Ferry Project may be suspended for the Winter, ITD continues to state the area is a construction zone.
Trimboli said most of the nine slopes around the area have bolts and anchors to help reinforce them, but because of winter weather, crews were not able to finish all of the slopes entirely.
"We knew that we weren't able to get some of the bolts and the anchors in on this cut," Trimboli said. "When you drill those holes, into the mountain you also have to an epoxy around them and that won't hold and form in cold weather. We ran out of time and we knew that."
During a construction project, it is typical for there to be movement and rocks to fall, according to Trimboli. ITD has a safety catchment built on the slopes to catch debris and rock. Trimboli added the tools were able to catch 98-99% of the fallen rock and snow, avoiding the road.
ITD said crews will now reassess all nine slopes on Highway 55 near Smiths Ferry with a geotechnical expert. Trimboli said they are also looking to add more signage in the area to inform the public they are driving through an active constriction zone where rockfall could happen.
"None of the slopes are finished," Trimboli said. "The work won't be done until the construction is over."
The Highway 55, Smiths Ferry Project is expected to be finished by the end of 2022.
KTVB reached out to the McCall Area Chamber, who puts on the McCall Winter Carnival, to see if they had been in touch with ITD in regards to traffic on Highway 55 before their event. They said they have not had direct communication with ITD, but have been made aware of updates and progress made on the highway.
"We trust that if the highway is open, it is safe for travelers," McKenzie Kraemer, the McCall Area Chamber spokesperson, said in an email. "While the rockslides are always a bit disruptive, we know the work on the highway is important for the future of the corridor. And Highway 95 has been a great alternate route!"
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