Regions
Kootenay Boundary.
Rain may weaken the upper snowpack Sunday afternoon. 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
The next weather system will initially bring rain on Sunday afternoon, changing to snow and lingering light flurries early next week. SUNDAY: 10-20 mm rain giving way to 5-10cm snow late Sunday. Moderate to strong southwesterly ridgetop winds. Freezing level around 2500 m lowering to surface overnight. 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.
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
A new crust 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. 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. Recent heavy rain to the mountaintops has rapidly shrunk the snowpack and has transitioned much of the snowpack from dry to moist snow. The major feature in the snowpack is a crust which was formed at the end of October can be found approximately 30cm above the ground in some locations. That said, 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
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.