Triggering large avalanches remains possible. Carefully evaluate conditions before venturing into bigger terrain.
Weather Forecast
THURSDAY: Clearing throughout the day with freezing levels around 1800m and light variable winds. FRIDAY: Mainly cloudy with light snow bringing as much as 5-10cm. Freezing levels reaching 1800m and light southwesterly winds. SATURDAY: Mainly cloudy with continued light snowfall totalling 5-10cm of accumulation. Freezing levels should drop to 1600m and winds are expected to be moderate from the southwest.
Avalanche Summary
Reports from Tuesday include several natural 40-60cm thick storm and wind slab avalanche up to Size 3. Recent natural persistent slab avalanche activity was also observed, with a report of a 1-2 day old Size 2, which released well below the top of the south facing start zone, suspected to have run on the early January surface hoar sitting on a crust. A continued cycle of natural loose wet sluffs reaching Size 2 on sun-exposed slopes, as well as cornice collapses, were also reported.
Snowpack Summary
Wet surface snow has refrozen into a supportive crust in most places; however, dry soft snow with new surface hoar growth may be found at treeline elevations on shaded aspects. Storm snow weaknesses down 40-60cm remain sensitive. Avalanche professionals are still monitoring the persistent weakness buried early January, which is now down 80-120 cm. In most places it is no longer sensitive to light triggers. However, in specific locations it still produces hard, but sudden results in snowpack tests.
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.