Although temperatures have dropped, a couple more cold nights are needed to neutralize instabilities in the upper snowpack.
Weather Forecast
An unstable weather pattern will bring flurries and up to 9cm of snow this morning. Freezing levels rise to 1500m this afternoon with an alpine high of -3. Ridge winds west 10-30km/h. A clearing trend begins early this evening with cold temperatures and clear periods overnight. A mix of sun and cloud forecast for Sunday.
Snowpack Summary
Cold temps overnight have cooled surface snow and formed a 10cm crust at lower elevations. The middle snowpack is still warm, with moist snow down to 70cm at treeline. Rapidly settling storm snow (30-40cm) is sitting atop 6cm wet layer that is showing weakness in stability tests. Lower snowpack is well settled. Suspect wind slabs near ridges.
Avalanche Summary
No new natural avalanches were observed in Glacier National Park yesterday.
Confidence
Timing or intensity of solar radiation is uncertain
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.
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.