Temporary closures became permanent Tuesday for both Chinook and Cayuse passes.
Citing hazardous conditions, the state’s Department of Transportation closed both passes – traveled by state routes 410 and 123, respectively – on Nov. 16. On Nov. 24, DOT maintenance crews buttoned up the passes for the winter.
The state agency had determined the avalanche risk was too great to allow traffic to safely cross Chinook Pass and Cayuse Pass. In addition, the National Park Service had expressed concern about debris and rocks falling onto the highway due to a lack of snowpack from last season’s unusually dry conditions. Snowpack helps keep debris and rock from loosening and moving.
The DOT closed SR 410 between Crystal Mountain Boulevard, about 12 miles northwest of the summit, and Morse Creek, five miles east of the summit. Cayuse Pass is closed within Mount Rainier National Park from Crystal Mountain Boulevard to Stevens Canyon Road.
Chinook Pass sits at an elevation of 5,430 feet and Cayuse is at 4,675 feet. Chinook Pass provides a route from the west side of the state to the Yakima Valley; Cayuse Pass allows travelers a route to circle around Mount Rainier.
WSDOT typically closes Chinook and Cayuse passes in late November due to hazardous driving conditions, avalanche danger, mountainous terrain and lack of cell phone service, all of which combine to make for unsafe winter driving.
The earliest Chinook closure on record came on Oct. 25, 2005; for Cayuse, the earliest closure came on Oct. 31, 1994.
Spring openings are largely at the discretion of Mother Nature, with a boost from DOT snowplow crews. Chinook is typically opened in May, although 2015 brought an unusual April 2 opening. The latest Chinook opening came in 1974, when motorists were off-limits until July 12.