Avalanche Forecast
Issued: Dec 9th, 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
Check the bond between the crust and snow before pushing into bigger terrain. Watch for pockets of wind effected snow near ridgelines.
Aim for low angle terrain with no wind affect for the best conditions.
Summary
Confidence
High - We have a good understanding of the snowpack structure and confidence in the weather forecast
Weather Forecast
A front pushes through the interior on Saturday bringing warmer weather, moderate to heavy snowfall and very strong ridgeline winds.
THURSDAY NIGHT: Cloudy with light accumulations overnight, light southwest winds.Â
FRIDAY: Mostly cloudy with light flurries increasing throughout the afternoon. Freezing level at valley bottom, alpine highs of -8. Moderate south-westerlies.Â
5-10cm of snow overnight.
SATURDAY: Snowfall increasing throughout the day, delivering 15-30cm and another 10cm possible overnight. Freezing levels climb to 1500m. Strong to extreme southwest winds.Â
SUNDAY: Light snowfall continues, with 5-10cm expected over the day. Winds ease back to moderate southwesterlies.
Avalanche Summary
Natural trigged storm slab avalanches were observed to size 2 near Fernie. Explosives and skiers in the same area also triggered storm slabs to size 2 yesterday, all failing on the melt freeze crust.Â
Over the last week natural and skier triggered slab avalanches have been reported in wind loaded features at treeline and above.Â
Note there are very few field observations this early in the season. If you venture out into the mountains, please share your observations and/or photos on the Mountain Information Network!
Snowpack Summary
20-40cm of recent storm snow sits over a thick and supportive melt freeze crust on all aspects below 2400m. Moderate to strong westerly winds have created deeper deposits in lee features in the alpine and treeline.Â
The snowpack holds several early season crusts about 20-30cm above the ground. Last week's heavy rain saturated the snowpack and has begun to break down this crust at treeline and below, creating a cohesive lower snowpack.
Snowpack depths range from 40-130 cm at treeline elevations. The snowpack tapers quickly below 1800m.
Terrain and Travel
- Be alert to conditions that change with elevation, aspect and exposure to wind.
- Wind slabs may be poorly bonded to the underlying crust.
- Seek out sheltered terrain where new snow hasn't been wind-affected.
Problems
Wind Slabs
Wind slabs are bonding poorly to the icy crust below. Expect conditions to remain reactive to human triggers. Approach ridge crest and cross loaded features with caution.
Investigate conditions before exposing yourself to steep or exposed features.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 10th, 2021 4:00PM
