Despite the MODERATE hazard rating, forecasters are being very conservative due to the snowpack structure. While it may be only "possible" to trigger, any avalanche will likely step down to the weak basal layers and be very large and destructive.
Weather Forecast
Tuesday will be cloudy with sunny periods and isolated flurries. Alpine temperatures are only expected to reach a high of -17 °C, which along with moderate westerly winds will contribute to significant wind chill values. Wednesday will remain cool with some light flurries.
Avalanche Summary
Two size 2.0 naturally triggered slabs occurred on Little Tent Ridge in the last 24 to 48hrs. These were both size 2.0 avalanches initiating near 2400m on a steep East aspect. Depths ranged from 40 to 60cm, with up to 80m wide propagations and ran for approximately 500m.
Snowpack Summary
1cm of new snow overnight. Fresh thin wind slabs have formed at Treeline and above. A test profile in the Ten Bowl area today revealed a 165cm deep snowpit with the entire bottom 100cm consisting of very weak facets and depth hoar. Moderate compression test results were found down 25 to 30cm. Moderate to hard test results occurred down 60 to 70cm within the facets, indicating the possibility for an avalanche to step down to the weak basal layers. The current snowpack structure is very concerning, and despite the recent lack of natural avalanches human triggering of a very large avalanche is possible.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.