Turnagain Pass

There were multiple natural and human-triggered avalanches yesterday in Girdwood and Turnagain Pass. Here is the list of activity:

Goat Mtn.: A large natural avalanche occurred in the Goat Couloir yesterday, propagating across the entire width of the couloir. The avalanche was most likely triggered by cornice fall or possibly by a smaller avalanche coming off of the rocks above the couloir.

Berry Pass: A skier triggered an avalanche 1-2′ deep and about 150′ wide just above Berry Pass. The avalanche failed on the 3/16 surface hoar layer, which was on top of a thin crust. Nobody was caught or carried in the avalanche.

Seattle Ridge: There were avalanches in Main Bowl, Zero Bowl, Warmup Bowl, Pyramid, and the front side of Seattle Ridge yesterday. Most were around  a foot deep and 100-200′ wide. These were failing on the 3/16 interface, and it is possible that the 3/16 surface hoar layer was involved in some of them. Some occurred naturally, some were triggered by snowmachines, and some were triggered by skiers. A snowmachine also triggered a large cornice fall, in which the rider and the machine fell several hundred feet. The rider was uninjured, but the machine was unrideable after the fall.

Tincan: A small natural wind slab released on the lower part of CFR ridge yesterday.

Skier-triggered avalanche on the east face of Pyramid. Nobody was caught or carried in the avalanche. Photo: Henry Munter 03.19.2022.

Natural avalanche in Seattle Ridge’s Warmup Bowl yesterday. Photo Kelly O. 03.19.2022

Natural avalanche in the Goat Couloir yesterday. Photo: Brian Sieknowski. 03.20.2022

Strong winds followed the storm that brought 1-2′ of snow over the second half of the week, and human-triggered avalanches will be possible today despite a quiet day weather-wise. We received reports of multiple natural and human-triggered avalanches yesterday (see the recent activity section above), and similar human-triggered activity is still possible. Some of these avalanches are failing on a layer of buried surface hoar that formed just ahead of the storm (more on that in Problem 2 below), which will make them slower to heal than a typical wind slab problem.

It will be important to approach steep terrain carefully today, taking the time to assess the snowpack where you are travelling. Be on the lookout for signs of unstable snow, such as shooting cracks, collapsing, and fresh avalanches. Use small test slopes to see if the snow is reactive before moving into bigger terrain. If you are trying to get into steep terrain, be sure to only expose one person at a time and watch your partners from safe spots. Don’t get lulled into complacency by the fair weather today, there is still a very real chance someone can trigger an avalanche big enough to bury, injure or kill a person.

Wet Loose: We can expect to see natural and human-triggered wet loose avalanches as the sun heats up southerly aspects today. These are usually not big enough to bury a person, but they do have the potential to trigger larger slab avalanches. Be aware of changing conditions through the day, and think about moving to shaded slopes as things start to heat up.

Cornices: Large cornices exist along ridgelines everywhere now. Yesterday’s incident with a snowmachine triggering a large cornice fall is a scary reminder to keep plenty of space from the edge as you travel along ridgelines. It is also important to limit time spent under cornices, especially as they heat up during the day.

Glide Avalanches: We got a report of the first glide crack releasing in a very long time yesterday in the upper Girdwood valley. There are active glide cracks throughout our advisory area- including in some high-traffic areas like above the Seattle Ridge motorized uptrack. These are unpredictable and very dangerous since they involve the entire season’s snowpack, so be sure to avoid spending time under them.

Serious wind loading in Seattle Ridge’s Zero Bowl late yesterday afternoon, with a natural wind slab avalanche in the background. Those wind slabs that formed yesterday will remain reactive today. 03.19.2022

After multiple human-triggered avalanches on buried surface hoar yesterday, persistent slab avalanches remain a concern today. There are two layers of buried surface hoar we are keeping track of right now, one of which is 6-12″ deep and the other is 1-2′ deep. These layers are slowly gaining strength with time, but they are still dangerous for now. As these layers become more stubborn, they won’t always give you clear feedback before triggering an avalanche so the best way to manage a problem like this is through smart terrain management. Avoid big terrain with features that increase the consequences of triggering an avalanche. These are things like cliffs, rocks and trees, or slopes that run down into creeks or gullies. As mentioned above, be sure to only expose one person at a time to steep terrain, and watch your partners from safe spots.

If you want to avoid the problem entirely, simply stick to lower angle terrain. With plenty of snow over the last few days, there is a lot of really good riding and skiing to be had without getting into avalanche terrain. These layers do heal with time, so patience is key when dealing with a persistent slab problem.

Skier-triggered avalanche in the Girdwood area yesterday. The avalanche failed on the 3/16 surface hoar layer, which was on top of a thin crust. The avalanche was 1-2′ deep and about 150′ wide. Photo: Mike Welch 03.19.2022.