Turnagain Pass

Additional load, either from rain or snow combined with high winds, will be stressing the persistent weak layers of snow we know exist in the snowpack. We have two concerning layers of buried surface hoar and the last two days we have seen remote triggered avalanches. We have also seen avalanches stepping down and failing in weak snow near the ground. If somehow the weather doesn’t turn you away from the mountains, it is important to realize that travel in avalanche terrain is not recommended. Stay out of runout zones. Up to an inch of rain is forecasted to fall to 3000′, maybe higher. Rain to can add weight and stress the snowpack quickly. Avalanches today could be very deep and dangerous. Above 3000′ we could receive over a foot of heavy wet snow. Cornices may also release naturally and trigger slopes below.

Yesterday morning observers noticed that another portion of the Seattle Ridge avalanche path, that was observed releasing on Sunday, had also slid. The trigger is unknown. Sunday’s slide is believed to have been a remotely triggered by snowmachiners on the ridge above. This is one of the avalanches that stepped down to the ground. 

Skiers yesterday triggered a large avalanche on Eddies that connected down the ridgeline, while ski cutting a lower angle slope nearby. They reported seeing shooting cracks and then watched the slope release. The crown was 1-5′ deep (average 3′), connected approximately 600′ down the ridge and ran 700′ down the slope. No one was caught or carried. The January 11th buried surface hoar is the suspected weak layer.

Eddies avalanche, 1.15.18. Photo: Susan Goodwin

On Sunday we recieved reports of a cornice triggered slab in Main Bowl. Here is a photo of the avalanche in motion. The cornice fall is believed to have been triggered by the snowboarders on the ridge. Photo: Eric Moore

As the rain falling today saturates the surface snow to 3000′ and possibly higher expect loose wet avalanches. They are often preceded by roller balls as rain falling on dry snow can quickly break apart the bonds between snow grains. Surface snow can start failing in a point and fan out. Wet loose avalanches can gain mass as they move down hill and gather snow. They could be quite dangerous today and not something you want to mess with. These can also be triggered by skiers or riders in steep terrain. If water actually moves through the slab to the weak layers or crusts below we could get a wet slab avalanches later in day.