Faced with heavy snowfall, avalanche risk and the subsequent hazardous driving conditions, authorities decided to close Chinook and Cayuse passes for the season the morning of Nov. 12.

“It’s difficult for crews to maintain those routes and manage avalanche control through wet and unstable conditions like this,” said Les Turnley, maintenance supervisor for the Washington State Department of Transportation. Approximately 20 inches of snow fell on the passes Nov. 12 and another major storm was anticipated later in the week.

Sitting at 5,430 feet above sea level, Chinook Pass is annually buried by deep snow that obscures state Route 410, the link between Enumclaw on the west and the eastern points of Naches and Yakima.

As usual, the pass is closed from Crystal Mountain Boulevard on the west to Morse Creek on the east, a spot five miles from the summit. Access to the Crystal Mountain Ski Resort on eastbound SR 410 remains open.

Chinook Pass typically closes in November and opens in April. In 2011, the pass closed on Nov. 11, but conditions can change year to year. For example, in 2008 the road was open until Dec. 15. One of the earliest closures on record came in 2005, when DOT shut down the highway Oct. 25; the latest closure was Dec. 18, 1974.

The earliest the pass has opened was April 5, 1973. The latest opening date came just a year later, when the roadway wasn’t cleared for traffic until July 12.

More information is available at the DOT’s Chinook Pass website, www.wsdot.wa.gov/traffic/passes/chinook.