Regions
Kootenay Boundary.
The effects of warm temperatures and rain on the snowpack may linger into Monday. Due to limited data it is CRITICAL to supplement this information with your own observations. Please post your observations to the MIN.
Confidence
Moderate - Due to the number of field observations
Weather Forecast
There may be some lingering flurries on Monday with more seasonal temperatures. The next system arrives on Tuesday, with lower freezing levels than we've been seeing lately. MONDAY: Cloudy with isolated flurries. Light to moderate westerly ridgetop winds. Freezing level around 1000 m.TUESDAY: Flurries (10-15cm possible). Light-moderate southerly ridgetop winds. Freezing level around 1000 m.WEDNESDAY: Clearing throughout the day. Moderate westerly ridgetop winds. Freezing level around 1200 m.
Avalanche Summary
No new avalanches reported; however, we currently have very limited observations in this region. Please submit your observations to the Mountain Information Network (MIN).
Snowpack Summary
Approximately 4-6 cm of snow fell Saturday night into Sunday, followed by rapidly warming temperatures on Sunday morning (to +3 Celsius at ridge crest in many locations).This new snow (or what's left of it) sits on the thick Nov 23rd rain crust, that formed at the end of last week's Atmospheric River (aka Pineapple) event. The depth of the snowpack varies greatly with elevation. Recent reports suggest the average depth is 100+cm in the alpine, 50-100cm at treeline, and decreasing rapidly below treeline where the primary hazards are rocks, stumps, and open creeks. Last week's heavy rain to the mountaintops really shrunk the snowpack and has transitioned much of the snowpack from dry to moist snow. A major feature in the snowpack is a crust which formed at the end of October and may exist approximately 30cm above the ground in some locations. That said, the thick November 23rd 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
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.