Turnagain Pass Avalanche Forecast

It is a bit of a transition day for the snowpack as colder air is moving in with sustained strong west winds. Overnight, temperatures have dropped to the mid 20’sF in the higher terrain and through the day, valley bottoms should see numbers near 30F. The wet layer of snow that capped the snowpack to ridgetops should now be a crust, or very soon will be. From the little we know now, the crust is variable; very thin to maybe an inch at Turnagain Pass and thicker to the south near Summit Lake. Not to mention, the crust should get thicker with elevation as warmer conditions were seen along the ridgelines vs the cooler air that was trapped in valley bottoms. Furthermore, the light rain that fell yesterday evening will have only added to the wet layer. We will see in the next couple days what damage this crust has done to the ski and riding quality.

The other thing that will give us some insight into how thick the crust is, is if the strong west winds forecast through the day will be able to transport any snow. Sunburst weather station gusted to 62mph around midnight and other stations have been reporting these strong winds. If you do head out, watch for any signs the winds are able to move snow. If this is the case, touchy wind slabs may be found, likely sitting on a crust.

Thin melt-freeze crust capping dry snow, near 1100′ on Eddie’s at Turnagain Pass. Allen Dahl, 12.28.21.

The other, and more uncertain avalanche issue, is what the buried weak layers are doing, or not doing, as the surface freezes up. These weak layers are under 3-5+’ of a dense layer of snow at Turnagain Pass, but are only under a couple feet on the southern end of the forecast zone and even less in places at Summit Lake. Although there were no avalanches that we know of the past two days, there were several large natural avalanches on Sunday, the first warm day, breaking in these old weak layers. One was just inside our forecast zone on Twin Peaks and the others were to the south in Summit Lake.

Moving forward, signs are all showing that at Turnagain Pass where the snowpack is thicker, it’s becoming very unlikely that a person could trigger a deep slab avalanche. The south end of the forecast zone and areas with a shallower snowpack are still a concern until they freeze up. Once they do it’ll be a question as to how stout surface crusts are and if any water that percolated under the surface and into the weak layers freeze, in order to determine if the weak layers are healed up or not. For today, be wary of these shallow zones if they are still harboring wet snow.

This all said, there is hope for some better snow quality for New Year’s as several inches of snow could fall early Friday morning. Cross your fingers!