In early November 2022, the area around Dry Creek experienced several inches of rain over several days resulting in a Nov. 5 debris flow that covered State Route 410. The roadway was blocked for several hours with mud, rocks, trees, and boulders several feet deep and the road's west embankment was damaged.
Crews were able to clear the roadway, however, Dry Creek has shifted to a new channel that flows into an undersized 24-inch culvert, rather than the larger four-foot concrete culvert it previously flowed through. The previous channel is permanently blocked by debris located outside WSDOT’s right of way on U.S. National Forest land. As winter progresses into spring, snowmelt and rain will increase runoff, which then increases the risk of roadway damage or washout.
WSDOT has determined that a two-stage emergency project is needed, first to minimize the flood risk from Dry Creek, and the second to install a longer-term solution that will result in a full roadway closure.
To maintain access to recreational and emergency access to Crystal Mountain Ski Resort and other businesses and residences, we installed temporary culverts across SR 410, which will allow us to maintain access during construction. Construction crews will install a 10-foot culvert in fall 2023 that will require a 75-hour full closure of SR 410.
Project received state and federal funding.
Heavy rains in early November caused a debris flow along Dry Creek, which plugged the creek's channel and sent water, mud and rocks over the highway.
When an early November debris flow caused Dry Creek to change channels, it overwhelmed a 24-inch culvert under State Route 410. The debris and water plugged the undersized culvert, causing debris and water to spill across the highway and scour the westside embankment.
Crews installed three overflow culverts beneath SR 410 in February 2023. The culverts will help the existing 24-inch culvert handle spring runoff until a larger, more permanent culvert can be installed this fall.
