By guest blogger Summer Derrey
Every year, our avalanche and maintenance crews work to clear the snow from Chinook Pass to reopen this section of State Route 410 for summer travel. It takes the work of crews from both sides of the state. Recently, I traversed the 5,430-foot pass to see for myself how the reopening effort works as crews clear Chinook from the east side.
Step 1. Safety first. Strap on an avalanche beacon, look for signs of potential avalanches like snowballs forming at the top of slopes, listen for the shhhh shhhh sound of snow sliding down the mountain and watch your step.
Step 2. Find the road. This year, it’s buried under 20 feet of snow.
Avalanche specialists knock down loose snow above the highway
Avalanche specialists clear the steep slopes of snow using several methods. Crews ascend to the ridgeline on skis, pushing into the snow intentionally triggering avalanches. They also pack in explosives and set charges. Occasionally, helicopters drop explosives in hard-to-reach areas.
Maintenance crews clear snow on the highway snow
Maintenance crews keep a safe distance behind the avalanche specialists while clearing the highway, using two bulldozers and two snow blowers. The pioneer dozer, led by team veteran Tom Martinson, climbs to the top of the snow pile and methodically carves a path 20 feet above the highway. Using a process called side-casting, Tom rocks the dozer perpendicular along the hill side pushing the snow off the cliffs with the dozer’s blade.
“There is a little less snow this year,” Tom said. “It’s been a piece of cake.”
Tom may have a sweet tooth, but the danger is always bitter sweet. Tom has to keep the snow and his rig level; otherwise, he could slide off the cliff. Meanwhile, Nick Zirkle is in the second dozer and uses a process called spading. He loosens the hard snow and ice with the dozer’s blade, creating a series of heaping piles for the blower to expel off the cliff. Doug Sutton is the veteran snow blower. His blower feeds the snow into the box, launching powder 40 feet in the air then whirling down the steep cliffs. John Rath is in the second blower and he’s like the dish washer, clearing every speck of snow off the highway.
Clearing snow is a slow and methodical process. It’s sort of like peeling layers off an onion one by one. By early May, after weeks of clearing, eastside avalanche crews meet up with the west side Greenwater crew near the top of Chinook Pass.
But the pass is not open yet.
Maintenance crews need to reinstall all the highway signs. The signs are removed each year; otherwise, avalanches would rip the poles out of the ground, pushing the signs to the valley bottom. Crews also monitor weather and avalanche danger. The snow build-up along the rock walls will loosen and topple onto the highway when conditions warm up.
Crews prefer to reopen Chinook once conditions are stable enough to keep it open. That way, drivers don’t get stuck on one side or the other and have to drive all the way around to White Pass on US 12.
Finally, crews unlock the gate and swing it open for six months of recreational travel. When will it open this year? Crews are on schedule to reopen a couple days before Memorial Day weekend, although that could change, depending on weather conditions and safety.
On average, crews clear 5.5 miles east of Chinook Pass using two bulldozers and two snow blowers. Four to six avalanche specialists knock down snow using 1,600 pounds of explosives in a four to six week period. Crews clear a minimum of 602,300 cubic yards of snow from the highway – not including the snow the avalanche specialists knock down from the mountain. It takes approximately 1,280 crew hours to reopen Chinook Pass each year.