Avalanche Forecast
Issued: Dec 2nd, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
wlewis,
Avalanche Canada
Wind loaded features may still exist at high elevations.
Just because danger is low, doesn't mean it's good snow...be prepared for hazardous travel conditions if you venture out today.
Summary
Confidence
Weather Forecast
The atmospheric river has finally left the building! The Kootenay Boundary will be clear and cold until Saturday morning when an active pattern returns.
THURSDAY NIGHT: Partly cloudy, freezing levels hit valley bottom. Moderate westerly winds.
FRIDAY: Clear with light northerly winds. Freezing level remains below 1000m, alpine high of -7.
SATURDAY: Snow begins in the early morning with light to moderate accumulations. Winds ramp back up to strong westerlies. Freezing levels remain below 1000m, with alpine highs of -5.
SUNDAY: Briefly clearing skies before snow returns Monday.
Avalanche Summary
Note that there are very few field observations from the Kootenay Boundary this early in the season. Backcountry users need to be skilled in assessing conditions and decision making. If you venture out in the mountains, please share your observations and photos on the Mountain Information Network.
Yesterday natural wet avalanches to size 2 were observed near Stagleap Provincial Park from steep treeline features on the Highway 3 corridor.
The Okanagan edge of the Kootenay Boundary also reported evidence of a natural storm cycle up to size 2. Explosive control work on the 30th produced several size 2 wind slabs on eastern aspects in alpine features, failing on a melt freeze crust.
Over the previous week several size 1.5 - 2 storm slabs have been triggered near Nelson, and a natural avalanche cycle size 1-2 was observed from north facing alpine start zones.
Snowpack Summary
Mixed precipitation and rain have left a melt freeze crust at the surface, overlying a very moist to wet upper snowpack with multiple crusts throughout. Isolated areas of sheltered alpine features may still hold dry wind effected snow.
The mid-November crust is down 40-90cm and is up to 10cm thick. At higher elevations the lower snowpack is a series of crust and facet layers with up to 20 cm of faceted snow sits on the ground. The entire snowpack was saturated at mid and lower elevations and is now refrozen.
Snowpack depths at treeline range from 50-100 cm, with alpine depths exceeding 120 cm in areas. Below 1700m, snowpack depths decrease rapidly with poor coverage in many below treeline areas.
Terrain and Travel
- Be alert to conditions that change with elevation and wind exposure.
- A crust on the surface will help bind the snow together, but may make for tough travel conditions.
Problems
Wind Slabs
Isolated wind slabs may be found at higher elevations. Investigate the bond between the slab and the old snow surface, they may still be reactive to a human trigger.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Dec 3rd, 2021 4:00PM
