Turnagain Pass

Several inches of new snow fell inTurnagain Pass on Tuesday combined with elevated ridge top winds. Yesterday several small natural slabs were noted in the Seattle Creek zone and activity near Byron Glacier was also reported. Several weak layers are buried within the top 1-2’ of the snowpack, most notably the 1/21 buried surface hoar which has been responsible for the scattered avalanche activity over the last two weeks. In Portage, where 8-10” of snow fell on Tuesday, recently buried surface hoar could be an additional new layer of concern in this area.    

Over the last week in Turnagain Pass, slabs have been relatively small and hard to find, considering the high volume of snowmachine and skier/rider traffic this area has seen. Don’t let old tracks fool you into thinking all these slopes are safe. If you see evidence of wind-pillowed snow or stiff snow over weak snow, be cautious in steep terrain. Snow that was once loose may have become more cohesive and ‘slab-like’ in the alpine on specific terrain features. Before committing to steep terrain, identify terrain traps like gullies, cliffs or rocks below and consider the consequences if even a small slab is released.   

*Deep Persistent Slab:  Weak snow can still be found near the ground at the upper most elevations in our forecast area, 3,000′ – 5,000′. Although triggering a Deep Persistent Slab is very unlikely, it is worth keeping in mind that poor structure does exist at the high elevations.

A thinner and weaker snowpack is more suspect in Summit Lake and the far Southern end of Turnagain Pass, where a skier triggered avalanche occurred on Saturday (Feb.3) on the East face of Twin Peaks, along the edge of our forecast zone. This avalanche stepped down into older layers of the snowpack. The party’s account can be found HERE and stay tuned for a near miss report coming soon. 

Wind affected snow was more obvious on the Northern end of Turnagain Pass yesterday. Photo of Western Bowl of Wolverine.

In addition to the 1/21 buried surface hoar we are also tracking a facet/crust combo between 2500’ and 3500’ that has shown propagation potential recently. 

Loose snow avalanches (’sluffs’): In Turnagain Pass a few inches of loose dry snow fell Tuesday and numerous small point releases were observed yesterday. In places protected from recent winds, expect this loose snow to be small in volume, but could slide easily in steeper terrain with the weight of a person. Watch your ‘sluff’ and be aware of the consequences below you.

Cornices: Cornices are unpredictable and can break further back along a ridge than expected. Give these features plenty of space.

Very shallow sluffs in steep terrain from the new snow on Feb 6. Photo taken in Seattle Creek yesterday.