Tumwater Canyon: Avalanche Alley

By Lauren Loebsack

If it seems like Tumwater Canyon on US 2 has been closed more often than usual this winter, well, your instincts are right. We’re seeing weather conditions that happen every several years that lead to increased avalanche hazards. But why can’t we just blast the snow down ahead of time, and what is different this year than last? Great questions! Let’s start with just what Tumwater Canyon is.

Tumwater Canyon is a winding 9 mile stretch of US 2 east of Stevens Pass. The terrain is a steep walled forest canyon bracketing the two-lane highway and the Wenatchee River. Those steep canyon walls are crisscrossed with almost 40 separate avalanche areas, meaning nearly the entire length of the road is directly adjacent to a known slide area.  That’s as many avalanche paths in those 9 miles as in there are in the 41 miles west of the canyon to Skykomish.

Tumwater Canyon has a long history of large, destructive avalanches and the railroad abandoned this route almost a hundred years ago in large part to avoid that impact to railroad facilities and trips.  Now when the risk of avalanche becomes too great the canyon is closed between Coles Corner (junction of US 2 and SR 207) and just west of Icicle Road near Leavenworth.

Tumwater Canyon winds its way between steep mountainsides on US 2 near Leavenworth.

Winter in Tumwater Canyon

This season’s weather pattern so far has included several early snow storms followed by intense freeze and snow/rain mix, creating a base state that worsens avalanche conditions through the canyon. That has already translated into several closures due to snow slides over the road and will likely mean more closures ahead this season. Historically, these heightened avalanche conditions average once every 10 to 15 years.

Unlike the avalanche paths on US 2 Stevens Pass, the narrow canyon and the challenging nature of the avalanche paths in Tumwater Canyon make doing proactive avalanche control almost impossible. During a closure, crews are evaluating conditions, mobilizing resources, and working to clear slides and reopen the road. Blowers and loaders are used to clear snow slides once conditions are safe to do so.

An avalanche that came down in Tumwater Canyon in winter 1997. Every several years we see more extreme winter conditions that lead to more closures due to avalanche danger.

Expect the unexpected

When heavy snow or rain is in the forecast, that means avalanche risk goes up. But slides can happen at any time when there is a heavy snow load in the avalanche pathways, so much like other winter travel, if you plan to drive US 2 east of Stevens Pass, there may be times when the canyon is closed. That means passenger vehicles can use SR 207 to Chumstick Highway but keep in mind that route is a county road that leads through residential areas and is not built for high traffic volumes or freight vehicles.  When Tumwater Canyon is closed the alternatives mean drivers need to be patient. It’s a good idea to add extra time to your travel plans.

A loader equipped with a snow blower cuts through a snowslide in Tumwater Canyon. The layout of the canyon is such that it makes doing avalanche control work nearly impossible.

In the rare event that you encounter a snow slide over the roadway, keep in mind these safety tips:

• Stay in your vehicle
• Turn around if you can and head back the way you came
• If you have cell service, call 911 to report the slide when it is safe to do so
• Our team is on the way

Know that our crews are doing everything possible to get you to your destination safely. And please, never attempt to pass closure points. The road is closed for everyone’s safety and passing the closure point puts not only you at risk but also maintenance crews and emergency responders.