The potential for large avalanches with the persistent slab problem still demands conservative terrain selection. Human triggering of this layer remains a possibility.
Weather Forecast
Light precipitation overnight Thurs with temperatures dropping drastically. Daytime highs in the -20s on Fri and even below -30 for Sat. Sunday will start the warming trend but is forecast to still be close to -20. Light snow forecast for Sunday again and possibly 5 to 10cm on Mon. There should be no significant solar radiation and Mod N winds.
Snowpack Summary
Thin sun crusts on SE to SSW slopes are becoming buried by light snowfall. Minimal wind effect observed at treeline, however there appears to be wind slab development in the Alpine. 80-130cm over the problematic late January facet crystals has rapidly settled into a hard slab. The potential for remote triggering and significant propagation remains.
Avalanche Summary
Natural avalanche activity has tapered off over the last couple of days. Lots of deep fracture lines still visible throughout the park from last week's big cycle. Human accidental and remote triggering of the persistent slab problem continues to be reported in nearby ranges.
Confidence
Wind speed and direction is uncertain
Problems
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.
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.