Fresh storm slabs will likely be reactive to human triggering, especially in wind loaded areas, and at upper elevations. Watch for signs of instability such as whumphing, cracking and recent avalanches.
Weather Forecast
FRIDAY NIGHT - Clear periods / east winds 10-15 km/h / alpine low temperature near -25SATURDAY - Mainly sunny / east winds 10 km/h / alpine high temperature near -25SUNDAY - Sunny / east winds 10-15 km/h / alpine high temperature near -20MONDAY - Sunny / northeast winds, 15-30 km/h / alpine high temperature near -15
Avalanche Summary
There were reports of numerous size 1-1.5 natural and explosives triggered avalanches on Friday.
Snowpack Summary
Up to 20 cm of new snow with moderate winds will be forming fresh storm slabs. Older wind slabs will be buried under the new snow and may be difficult to detect.A weak layer of facets (sugary snow) and surface hoar (feathery crystals) that was buried in mid January is down approximately 40-80 cm. This layer is most prominent between 1600 m and 1900 m, but it has been found up to 2200 m in some areas. This weak layer may exist in combination with a crust on south facing slopes. Recent snowpack tests and avalanche reports suggest that this layer remains reactive to human triggers.The bottom half of the snowpack is composed of weak, sugary facets.
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.