Turnagain Pass

We received word of a large remote-triggered avalanche yesterday in Palmer Creek near Hope (details here). The avalanche was triggered from flat terrain below the slope, and ran across the bottom of the valley. It carried multiple snowmachines, partially burying one. No people were caught or carried. This is the fourth very large remote-triggered avalanche in the area over the weekend, including two on the back side of Seattle Ridge, and one in the Skookum Valley.

This very large avalanche was triggered remotely from the flat terrain below the slope that released. This is the fourth remote-triggered avalanche that we know of in the past two days. Photo: Seth Kiester. 03.26.2023

The snowpack showed us what it is capable of this weekend. We have seen four very large remotely-triggered avalanches in the past two days, and the problematic setup that is making this possible is going to take a long time to go away. These avalanches have been triggered from low-angle terrain connected to steeper slopes, and in some cases people were standing up to a half mile away when they triggered the avalanche. In some cases, people have triggered releases on multiple slopes and multiple aspects at the same time (see more info on avalanches on Seattle Ridge here and here). All of these avalanches have run far into valley bottoms (See more here from the massive avalanche in the Skookum Valley Saturday), and we are really lucky that nobody has gotten caught in any of them.

Sometimes these deep slab avalanches are hard to predict, with weak layers lurking under the surface and a high amount of uncertainty as to whether a person can actually trigger a large avalanche. This is not one of those ‘hard-to-predict’ times. All of the recent avalanche activity shows us that we are dealing with a very dangerous snowpack, and it is nothing to mess with. We’ve seen activity on both sides of the highway at Turnagain Pass, multiple large avalanches in the Placer/Skookum area, and more large avalanches around the periphery of our advisory area in Summit and Palmer Creek. For now the only way to manage the problem is to avoid traveling on or below steep avalanche terrain.

If our video from the crown of the large natural avalanche on the north side of Sunburst does not load, you can view it here.

We are looking at another day of warm temps and partly sunny skies. It will be a race between the warming daytime temperatures and increasing cloud cover that will determine whether we see loose wet avalanche activity this afternoon. If the clouds build early enough, it is likely the snow will stay dry even on solar aspects as it did yesterday. If things do end up heating up enough this afternoon, or if there is enough sun shining later in the day, we expect to see loose snow avalanches this afternoon. These will likely be preceded by rollerballs releasing, and it should be noticeable that the snow surface is becoming moist as things start to heat up. If things do get warm enough, there is a chance that loose snow avalanches failing near the surface may trigger something bigger deeper in the snowpack (see problem 1 for more on that). Pay attention to changing conditions while you are out today, and be ready to move to shaded slopes if you notice things heating up this afternoon.