Be mindful of the persistent slab problem lingering at lower elevations as you search for snow that has been sheltered from recent winds.
Weather Forecast
Friday night: Clear. Light northeast winds.Saturday: Sunny. Light northeast winds. Alpine high temperatures around -20.Sunday: Sunny. Light east winds. Alpine high temperatures around -16.Monday: Sunny. Light northeast winds. Alpine high temperatures around -13.
Avalanche Summary
No new avalanches were reported on Wednesday.Avalanche activity on the mid-January weak layer described in our snowpack summary has seen a steady decline, however snowpack tests continue to show strong potential for reactivity at this layer, especially below treeline. This shows persistent slab avalanches are still possible for a skier or rider to trigger in specific locations. The consequences for doing so remain high.
Snowpack Summary
Recent moderate to strong northerly ridgetop winds have created wind slabs on lee features at treeline and above. Below this wind affected layer, older buried wind slabs exist on a variety of aspects. These remain a concern for overlying facets (weak, sugary snow), causing them to remain reactive for longer than is typical for a wind slab problem.A weak layer that was buried in mid January is down 50-60 cm and is especially prominent below treeline. This layer consists of surface hoar (weak, feathery crystals) and facets, and may be combined with a crust on south facing slopes. Avalanche activity on this layer has been on the decline, but snowpack test results continue to indicate this layer may still be possible to human trigger in specific locations. It has been most reactive in sheltered openings at lower treeline elevations and below.The lower snowpack is generally considered to be strong, except for shallow, rocky areas where cold temperatures continue to facet (weaken) the snowpack.
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.