Avalanche conditions in the alpine are EXTREME. Avoid avalanche terrain.
Weather Forecast
Unsettled, stormy weather conditions continue through the forecast period. Overnight Wednesday: Snow amounts 15-30 cm. Ridgetop winds strong from the SW. Alpine temperatures near -10. Thursday: Snow amounts 20-40 cm. Ridegtop winds strong from the SW. Freezing levels 1200-1400 m. Friday: Light-moderate snow amounts. Strong SW winds. Freezing levels falling to 600m. Saturday: Flurries. Possible sunny breaks, and freezing levels falling to valley bottom.
Avalanche Summary
On Tuesday a natural avalanche cycle occurred up to size 3 on N-NE aspects. Cornices reached their threshold and triggered slopes up to size 2.5 below. On Monday, a skier was partially buried and two others escaped a size 2 slab on an east aspect at 1500m, which failed on a crust. Natural and skier-remote triggered avalanches to size 3 were also observed on a variety of aspects and elevations, some failing on the mid-February weakness. Crowns were up to 150cm deep. Every day of the last week, avalanches have been triggered either naturally, remotely or accidentally by backcountry travelers. With forecast heavy snow amounts, and strong winds, natural avalanche activity will continue. Thursday may be a good day to hunker down, or tear up your local ski resort!
Snowpack Summary
Stormy conditions continue! Over 1m of storm snow has fallen, accompanied by strong SW winds. Storm slabs and wind slabs continue to build. Cornices are large, some reaching threshold and triggering the slopes below. For the most part, the new storm snow is right side up (lower density snow on top) and easy to moderate shears exist within the upper meter. The additional weight of new storm and wind slabs may step down and trigger a deep weakness, formed in mid-February. On Monday, reports of avalanches failingon this layer naturally and with a remote trigger started coming in. Recent test results on this layer produced hard sudden planar results down 120cm in the snowpack (DTH24 SP dwn 120cm on FC/RG 0.5). Very large avalanches are possible, which could be remote-triggered, triggered mid-slope, and/or propagate into low-angled terrain.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.
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.