Turnagain Pass Avalanche Forecast

Winter has begun, and we are starting to sort out the characteristics that make up our snowpack. So far it seems like there are three main things to keep in mind if you are trying to get out and enjoy the early season snow:

• The snowpack is thin and variable. There is about 2′ of snow on the ground on average, but this really varies even over small distances. In some pockets we are seeing 3-5′ of snow or more, while other slopes were blown down to bare ground during the northwesterly wind event over the past few days. Obviously we will be inclined to seek out the best coverage in the deeper pockets, which brings us to our next point to consider:
• Wind loaded slopes will be more dangerous that non-wind loaded slopes. This is kind of a bummer since it means the slopes with the best coverage potentially have the worst stability right now. Yesterday while we were out on Seattle Ridge we experienced multiple collapses, a classic warning sign indicating unstable snow. All of the collapses we experienced occurred on terrain features that had been wind loaded at some point. Some of these were loaded during Wednesday’s storm, and others were more recently loaded. These collapses were also closely tied to the third piece of the puzzle:
• There is a thin layer of faceted snow at the ground on some slopes, which formed from the little bit of snow we got at the end of October. This layer contributed to the wide-propagating avalanches during or immediately after the 11/2 storm event. There was activity throughout Turnagain Pass near the end of that storm, with large avalanches reported on Tincan, Magnum, Lips, and in the Seattle Ridge back bowls. We found the layer of facets in multiple pits on Seattle Ridge (details here), and it has also been reported on Sunburst (details) and Tincan (details). Time will tell if this becomes a problem layer for the long term, or if it heals quickly. For now it is worth keeping in mind while choosing terrain.

It is an exciting time of the year, and it can be tricky navigating the early season conditions. I will be keeping these three factors in mind while choosing terrain, and layering on top of it a thick blanket of uncertainty since we really have limited snowpack info this early in the game.

We will continue issuing periodic conditions updates for the next two weeks, and plan on switching to daily forecasts starting Thanksgiving Week. In the meantime, if you are getting out please take a few minutes to submit an observation. Any info is greatly appreciated, and it can be as simple as a few pictures and note about how good the snow was. We are data hungry this time of year, and your observations are incredibly helpful.

Weather Outlook

Looking ahead, we are expecting to enjoy one more day of high pressure with clear skies and cool temps before we switch back to a southerly flow pattern that will likely bring warmer temperatures and precipitation (hopefully the white fluffy type) early to mid-week. Stay tuned for a mid-week conditions update!

This very large avalanche propagated across most of the west face of Magnum sometime near the end of the 11/2 storm event. Submitted anonymously 11.03.2022

Slab avalanches in Tincan’s Common Bowl, failing on the ground. These also occurred near the end of the 11/2 storm. Photo: Andrew Waldo, 11.04.2022