Consider avalanche danger to be HIGH in areas that receive rain on top of 30 cm or more of dry snow. Avoid exposure to avalanche terrain during periods of rapid loading by rain, snow, or wind.
Confidence
Low - Due to the number of field observations
Weather Forecast
SUNDAY: 5-15mm rain or snow depending on elevation / Moderate to strong westerly ridgetop winds / Freezing level rising to around 2200 mMONDAY: Cloudy with isolated flurries / Light to moderate westerly ridgetop winds / Freezing level around 1200 mTUESDAY: 5-10 cm of snow / Light to moderate westerly ridgetop winds / Freezing level around 1500 m
Avalanche Summary
On Friday, no new avalanches were reported in this region. Natural avalanche cycle expected on Sunday in areas where rain falls on dry snow. 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 5-10cm of snow at treeline and above. Wind re-distributing this new snow may have formed small wind slabs on lee features, such as below ridgetops and in gullies. The depth of the snowpack varies greatly with elevation. Recent reports suggest the average depth is 200+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 November 11th and can be found approximately 100cm down at treeline elevations. 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 Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.
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.