New snow sitting on a hard crust may have created reactive storm slabs at treeline and above. Due to limited data it is CRITICAL to supplement this information with your own observations. Please post your observations to the MIN.
Confidence
Low - Due to the number of field observations
Weather Forecast
SATURDAY: Mainly cloudy / Light southwesterly ridgetop winds / Freezing level around 1500 mSUNDAY: 5-10 cm new snow in the afternoon with an additional 5-10 cm overnight / Moderate to strong southwesterly ridgetop winds / Freezing level around 2400 mMONDAY: Cloudy with isolated flurries / Light to moderate westerly ridgetop winds / Freezing level around 1500 m
Avalanche Summary
On Thursday, no new avalanches were reported in this region. However, we currently have very limited observations in this region. Please submit your observations to the Mountain Information Network (MIN).
Snowpack Summary
A new crust was formed on Thursday as temperatures cooled and the rain soaked snow surface froze and then was covered by 15-25cm of snow at treeline and above. The new snow has created fresh storm slabs sitting on a crust. The depth of the snowpack varies greatly with elevation. Recent reports suggest the average depth is 150+cm in the alpine, 100-150cm at treeline, and decreasing rapidly below treeline where the primary hazards are rocks, stumps, and open creeks. The major feature in the snowpack is a crust which was formed around Halloween can be found approximately 100cm down at treeline elevations. However, the new surface crust will temporarily reduce the likelihood of triggering on this layer. We currently have very limited snowpack observations within this region and it is critical to supplement this information with your own observations.
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.
Loose Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.