Sawtooth & Western Smoky Mtns

Dense, freshly formed wind drifts will be sensitive to your weight in steep, upper elevation terrain and will be building in size throughout the day. Triggering a large avalanche that breaks widely on buried weak layers is still a concern. While the likelihood of this is gradually decreasing, it is still a worrisome possibility. Don't expect any signs of instability before triggering an unsurvivable slide. These avalanches can be triggered from long distances away and run into terrain far below. 

With up to 14 inches of fresh snow falling by this evening and sustained moderate winds, you will not be able to ignore new snow issues as you climb higher in terrain today. Dense deposits of wind-drifted snow will become larger throughout the day, and if the winds shift to the north earlier than forecasted, there will be close to 2 feet of snow available for transport. Even when small, these slabs as well as loose snow sluffs can have severe consequences if they knock you off your feet in the wrong terrain and send you skyrocketing head first into the landscape. With large cornices already well-established in the Sawtooths (see photo), these large features can grow past their breaking points today and start to fail. All of these new snow issues can serve as triggers for the persistent slab dragon that lurks deep below...

Two days ago, a group of skiers remotely triggered a large avalanche on Saviers Peak. Without receiving any signs of instability, the slide broke 100 feet below where they stood on the ridge above. This slide broke on persistent weak layers 1-2 feet down in the snowpack, and ran to the valley bottom over 1000 feet below. Three days ago, a group of skiers in the Baker Creek drainage triggered an enormous collapse that traveled over 1,500 feet, shattering the snowpack across a broad area. The skiers were on their third lap up their skin track when they felt the slope collapse and watched fractures spiderweb the snow in front of them. On a steeper slope, this collapse would have triggered a massive avalanche. In both cases, these were the first signs of instabilities.

Navigating our widespread persistent slab problem is no walk in the park. There is no golden rule, or set of rules, that will give you the green light to ski a slope. We can give ourselves broad brushstrokes of terrain characteristics as aids for picking slopes that are less likely to slide and that have less severe consequences. Slopes where you are most likely to trigger these slides are going to be wind-loaded, thin, rocky, alpine terrain with steep rollovers. Terrain where you're less likely to trigger an avalanche and consequences will be lower are going to be evenly covered, with clean runouts that have no terrain traps at the bottom (trees, rocks, cliffs to be strained through). With this being said, these are not rules but trends. 

To move through the mountains is to accept uncertainty — we can never control every aspect of a day. Terrain selection is how we get to pick how much uncertainty we accept. While there are many slopes of avalanche terrain you can ski and not trigger a slide, the chance of triggering a large, unsurvivable slide remains. As a mentor, and fellow forecaster who passed away last week told me on my first day out in the field with him: "We study layers and grains, collect observations, and think that we know. But you can't know. And neither can I. We're always playing a game of odds." He reminded me of this throughout the season, asking me, "Do you really know that?" many times while still enjoying many days of great skiing in avalanche terrain. Try to remind yourself of this as you're moving through the mountains. If you choose to enter avalanche terrain, you can use your terrain selection to stack those odds in your favor.