Turnagain Pass

It has been 6 days since two separate snowmachine triggered avalanches occurred in Turnagain Pass zone, one in Seattle Creek and the other in Lynx Creek. Sunny weather this week has allowed many people to venture far and wide, testing a lot of terrain without incident. The likelihood for someone to find and trigger a large slab is decreasing as the snowpack adjusts, but the poor snowpack structure remains and the consequences are scary. For example the avalanche in Lynx Creek had a crown that was 1000’ wide and ran 1500’ into a large terrain trap. The slab was 1-4’ thick and was sitting on weak faceted snow near the ground. Both near miss avalanche accidents last week were triggered in thinner areas of the snowpack, on slopes that already had tracks on them. The tricky part about this particular avalanche problem is that it is very difficult to assess. Obvious signs like whumpfing and shooting cracks are unlikely and stability tests may not be reactive. Just because a slope has tracks on it does not mean it is safe. Likely places to trigger a deep persistent slab will be near rocks or in scoured zones. Likely triggers are large: snowmachines, groups of people or cornice falls. Identify and avoid terrain traps (like large gullies,) and always practice safe travel protocol, by only exposing one person at a time on steep slopes. 

Click HERE to read the detailed near miss report about the Seattle Creek avalanche where one snowmachiner was fully buried, and a quick rescue by his partners saved his life. Click HERE for the initial details about the Lynx Creek avalanche where luckily no one was caught. Stay tuned as we will be posting more info about this avalanche soon.

A photo of the crown on a NE aspect of Seattle Ridge avalanche near the Headwall. Photo taken 2/6/17 by Wendy Wagner

Wind slabs: Light flurries today combined with Easterly ridge top winds 10-20mph are expected and may form small isolated wind slabs on leeward features. There is also up to 8” of older loose snow available for transport. These wind slabs could from on a hard sun crust on Southern aspect and may be extra tender. Keep an eye out for blowing snow and pay attention to which slopes may be more loaded. Avoid pillowed or drifted snow or areas with stiff snow over soft snow on high consequence terrain.

Loose snow: With 4-8″ of loose snow on the surface over a dense base and possibly a few inches of light dry snow today, watch your sluff. 

Sun: It’s that time of year again. Although the sun is not expected today, should it appear, it has the potential to weaken the surface snow and make wind slabs and loose snow easier to trigger. 

Sun crust found on a SE aspect of Tincan early this week. Photo courtesy of Brooke Edwards

This weekend cornice cracks were reported along the back bowls of Seattle Ridge making some of these cornices extra sketchy. A few chunks have been triggered this week. Also these features can be difficult to see in poor visibility. Remember these unpredictable hazards can break farther back onto a ridge than expected and have the potential to trigger an avalanche on the slope below. Give cornices extra space and avoid being under them.