Idaho 55 highway project monitored for avalanche risk as work pauses for winter

Construction on the troublesome Idaho 55 highway project near Smiths Ferry has paused for the winter, presenting potential avalanche concerns along the sensitive mile-long mountain stretch.

Final touches on the years-long project to widen a section of the Valley County highway are slated for spring 2023, though now may carry over into the summer, depending on when crews can restart operations after the snowy construction off-season. Additional safety enhancements, including snow fencing designed to limit future avalanche risk in one area, will be the focus of that work, according to the Idaho Transportation Department.

In the interim, ITD officials are closely watching the project zone for avalanche risk as they pause construction for the winter and early spring. ITD will temporarily close the road if conditions warn of a potential slide and direct motorists to Interstate 95 as an alternate route until Idaho 55 is safe to reopen.

A weather station was installed on the rock slope where work remains unfinished, so the agency can receive real-time data on temperatures, weather forecasts and snowpack levels. Plow operators will be available at all times, ITD said.

Last winter, construction crews installed shipping containers at the base of a different rock slope within the corridor as a safety barrier, blocking potential slides from reaching the road. ITD officials previously told the Idaho Statesman that the temporary measure never factored, with no slides in the project zone after that point.

“Our commitment to safety has not wavered on this project,” John Tomlinson, an ITD spokesperson, told the Statesman in a statement last week. “We want to reassure the public that we have crews, equipment and experts monitoring the conditions and there are no more planned or foreseen closures. Winter weather is variable, and so we will be responsive and adapt as necessary.”

‘Major construction’ finished, ITD says

Road-widening work on the section of Valley County highway, which acts as a primary thoroughfare between Boise and McCall, began in September 2020. Construction was originally scheduled for a fall 2022 finish at a total cost of $30.8 million including some expected support costs, ITD said.

But at least six rock slides dating to March 2021 on several of the nine rock slopes on the corridor’s west side led to delays and a ballooning budget. The largest of the slides in November 2021 closed the road for nearly three weeks and cost $9 million to clear and reopen to the thousands of motorists who drive it every day.

With those extensive cleanup costs, the project’s total price tag once completed is currently estimated to be more than double its original cost — at as much as $62.6 million, if a $10 million contingency fund is needed to wrap up work next year, ITD said. Another $1.8 million was spent on the original design and construction plans.

“Based on what we know now, our team is confident in the estimated total cost and we hope to be under that amount,” Tomlinson said.

The Idaho 55 project will cost no less than $52.6 million at its end, ITD officials told the agency’s board at its November meeting. That total includes $1.8 million paid to Boise-based engineering firm McMillen Jacobs Associates for some redesign work once the rock slides began to hamper construction.

Despite some significant and unforeseen setbacks, “major construction” is complete, ITD officials said.

“The unpredictable landslide in November 2021 was basically an additional project within the overall project,” Tomlinson said. “The good news is that the new safer highway alignment with new pavement, wider shoulders and guardrails was completed on time.”

‘We had to get this fixed’

The project along what officials call the “white-knuckle section” of Idaho 55, adjacent to the Payette River, was envisioned for years to improve road safety. Over the past two decades, the 1-mile stretch had 154 crashes through 2021, ITD data showed.

More than half of those crashes during that period included injuries, and one involved fatalities. A Garden City couple in their 70s drowned when their SUV went down the embankment and into the river in June 2017.

Before that, in April 1996, a 17-year-old girl from Smiths Ferry died after she was thrown from a pickup truck when it slid off an embankment and overturned into the river. The 25-year-old driver, who was found to be over the legal alcohol limit, according to a Valley County Sheriff’s Office incident report obtained by the Statesman, later pleaded guilty to vehicular manslaughter and sentenced to prison, court records showed.

Julie DeLorenzo, the ITD Board’s District 3 member that represents southwestern Idaho, acknowledged at the board’s September meeting the considerable engineering challenges of the project, which added to its costs. She referenced the 1996 fatal crash and the need for the safety enhancements as the agency’s ongoing objective.

“That’s why doing we’re this project. I don’t want that to happen ever again,” DeLorenzo said. “I know it costs a lot of money, but we had to get this fixed.”