Mad River Union
HUMBOLDT – The closure of state Route 299 is expected to be lifted sometime this week as construction of a detour around a landslide area finishes.
An update on the status of one of Humboldt County’s few west-to-east access routes was presented to the Board of Supervisors at its Jan. 10 meeting.
The slide area is about 30 miles west of Weaverville near Big French Creek in Trinity County. It has been problematic since last year, when smaller slides caused partial, one-lane closures.
Matt Gowen of the California Department of Transportation (Caltrans) described the slide as being unique for its persistence. “With this one, the main slide came down but it continued to shed rocks on us,” he said, adding that the slide area extends up to 700 feet above the roadway and “it took us awhile to determine what it is we’re going to do here.”
Drought conditions suspended slide activity, but after recent rains, parts of the mountainside came down and massive deposits on the roadway completely closed the route on Dec. 12.
Gowen described how fall and early winter rains intensified the slide’s severity.
“The mountain came alive again and massive amounts of material came down,” including one rock that was “literally as big as a house,” he said. “That gave credence to what we’d been saying all along – that the road’s closed for public safety.”
Gowen said initial plans to contain the slide and build a catchment area were determined to be insufficient. Caltrans chose to remove material from the top of the slide and build a detour road adjacent to and above the existing road to move travelers away from the slide area.
It is a $6 million fix that is considered to be temporary, but Gowen said the slide is so dynamic that a long-term plan is still undetermined.
Supervisor Ryan Sundberg thanked state Sen. Mike McGuire for his support of funding for the detour. Relaying a question he had received via email, Sundberg asked about the timing of Caltrans’ work, as partial closures started last summer and work did not appear to start until fall.
Gowen said slide conditions and lack of an emergency declaration prevented earlier work.
Some local travelers have been using former logging roads as detours, but Gowen said Caltrans does not recommend the use of those roads, as they are narrow and not safe for general traffic. Most travelers are using Highway 36 to get in and out of the county.
Gowen said completion of the detour roadway has been delayed about a week due to rains, but “it’s still looking good for the week of the 15th.”