Above 2,500ft Considerable
1,500 to 2,500ft Considerable
Below 1,500ft Low
Degrees of Avalanche Danger ?
Problem #1: Wind Slab
Distribution: On southwest through southeast aspects and cross-loaded terrain features, treeline and up. Wind loading over the last week has created areas of hard slab in the alpine with weak snow underneath. New wind loading on top will only make the problem worse. Slopes below ridgelines, and any other areas of recent wind loading will have cold, dry hard slabs that need to be avoided. Stay well away from cornices and the wind-loaded slopes beneath them. Stick to wind-sheltered areas where the snow is still soft.
Problem #2: Deep Slab
Distribution: Isolated, on wind-blown slopes with thin snowpack less than 1m thick. Generally around ridgelines, and anywhere rocks are exposed or thinly buried. All aspects. Elevations above 3000ft. In the Pass zone, there are extensive weak facets at the ground in any areas of thin snowpack. We’re now seeing natural slides on this basal facet layer in areas north of the Pass (see photo). Even in places with deeper snow, there remain trigger points near rocks/thin areas. If you were to trigger a slide on this layer, it would be a deep, wide, hard slab avalanche with deadly consequences. This is a low-probability high-danger situation that is very difficult to manage, so it’s best to exercise caution. Be very careful to avoid rocky trigger points and thin areas. Stick to slopes with a deeper, more uniform snowpack.
Recent Avalanche Activity
The last observed avalanche activity was during the last storm cycle Feb 11-15th. There was a natural avalanche cycle within the new storm snow, with widespread D2-D3 slides on all aspects. These were dry slabs above 4000ft, and some nasty wet slabs below that level. A few large avalanches occurred, with crowns up to 2m tall. Some slides hit the valley floors and lower runouts.
Snow totals are expected to be 8-14″ by Monday evening. Moderate north winds will be continuing with alpine temperatures 5-15F.
Low pressure over the Gulf will be spinning light-moderate snow into our area through the week. A few impulses may bring heavier bursts of snow Tuesday and/or Wednesday, but the timing is hard to pin down right now.
Additional Info & Media
This is an important time to practice good group management skills and risk-reduction. This means keeping your group spread out while traveling in avalanche terrain. Ride one-at-a-time in any areas of risk, and only group up in safe zones well out of harms way. Evaluate each slope carefully, have an escape route, and a plan for what to do if an avalanche occurs. Always make sure every rider has a beacon, shovel, and probe, and knows how to use them.