Turnagain Pass Avalanche Forecast

Several days of generally quiet weather is allowing the snowpack to slowly adjust and theoretically avalanches are becoming less likely to trigger. There was a spike in Easterly winds on Friday afternoon that loaded certain slopes, but other than this no load has been added since Wednesday. Time is on our side, but with that said, we have several weak layers in the snowpack. The pack is getting to the point it may not show any signs of instability until an avalanche is triggered. Many folks may ride/ski a slope before someone hits just the wrong spot. It’s a tricky situation. 

Points to keep in mind if you are headed out today and the visibility opens enough for travel above treeline:

1-  Slab avalanches 1-3′ thick will be possible to trigger, and may even remain likely to trigger on certain slopes
2-  The snowpack is likely to ‘feel’ stable and not show its cards till it’s too late (several tracks may be on a slope before it releases)
3-  Safe travel protocol is key to stacking the odds in your group’s favor if choosing to ride upper elevation avalanche terrain (i.e., exposing one person at a time)
4-  Avalanches triggered can be large and unsurvivable

Over the past week we have been concerned about a layer of buried surface hoar that sits 1-3′ deep (buried by the New Year’s storm). This layer remains reactive in pits between 2,000-3,200′, yet it remains untested at the higher elevations. We are also concerned about a layer of faceted snow that sits near the ground on slopes that avalanched in early December. Both these issues are in the top three feet of the snowpack and are responsible for these ‘persistent slab’ avalanche problems. Quick note of thanks to the many folks writing in to help us assess the layers!

Plumes on the Twin Peaks near Silvertip, created by Easterly winds on Friday afternoon.

Snowpack just above treeline on Tincan – buried surface hoar main concern for human triggered avalanches

Many tracks on a slope – snow is complex, we know there are weak layers lurking, don’t assume the slope next door will allow that many tracks.

Seattle Ridge, just open to motorized use – very little information for this zone, please let us know what you see if you head this way!

In the Alpine, above 3,000’, human triggered large and dangerous deep slab avalanches are still possible. Weak sugary snow (basal facets) near the ground is creating a low probability/high consequence avalanche problem that is impossible to outsmart. This will take a long time to heal. A big trigger like a snowmachine or a slab avalanche in the upper layers of the snowpack may be enough force to initiate a deep slab avalanche. Likely trigger spots will be in thinner areas of the snowpack that are connected to large, loaded slopes. Cautious route-finding is essential. This includes thinking about the remote trigger potential from below.

Changes coming to this advisory page tomorrow! Please see this short document and video about the changes and reasons for them.

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