Avalanche Forecast
Issued: Jan 8th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
ghelgeson,
Avalanche Canada
Avoid ridge crest and rock outcroppings in the alpine where you're most likely to trigger hard slabs. Softer slabs at treeline may rest on buried surface hoar making them surprisingly touchy. More snow and wind is on the way which is expected to exacerbate the wind slab problem.
Summary
Confidence
Weather Forecast
Quite a bit of snow and wind in store for the forecast period. We’ll be watching these snowfall amounts closely.
FRIDAY NIGHT: Freezing level at valley bottom, strong southwest wind, 5 to as much as 10 cm of snow possible.
SATURDAY: Broken cloud cover, freezing level at valley bottom, strong south wind, a few cm of snow possible during the day.
SUNDAY: Overcast, freezing level at valley bottom, strong south/southeast wind, 5 to 10 cm possible during the day with another 5 to 10 cm Sunday night.
MONDAY: Overcast, freezing level at valley bottom, strong south wind, 5 to 10 cm of snow possible.
Avalanche Summary
We received word of a snowmobile triggered wind slab avalanche north of Log Cabin that occurred on Thursday. Sounds like everyone is okay, but the avalanche occurred at treeline in relatively benign terrain which speaks to the reactivity of fresh wind slabs that may rest on surface hoar.
Snowpack Summary
Firm slabby snow can now be found in almost all wind exposed terrain. The predominant wind has been from the south but some north wind snuck in Thursday night meaning wind affected snow can be found on all aspects.
In terrain around treeline there may be fresh wind slab sitting on surface hoar that is capable of producing large human triggered avalanches.
A buried crust formed in early December can be found 60-100 cm below the surface, but most reports suggest the snow is quite well-bonded to this crust.
The lower snowpack is strong around White Pass, but there is potential for a generally thinner and weaker snowpack structure to exist in inland areas such as the Wheaton Valley.
Terrain and Travel
- Avoid freshly wind loaded terrain features.
- Be aware of the potential for wide propagation.
- Sheltered slopes at lower elevations will offer the best riding.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Problems
Wind Slabs
Wind slabs. They're now everywhere, and we expect them to remain problematic through the weekend as more wind and snow come into the picture.
Up high the wind slabs are fat and hard. In the alpine you need to be careful to avoid the spots where the slabs are thinner and thus easier to trigger. Ridge crest is one of those places where hard slabs are often triggered. Rock outcroppings are another problem area.
At treeline the slabs are softer, but easier to trigger. At this elevation slabs may be resting on surface hoar which could make them quite sensitive to human triggering. Problem areas at treeline include convexities and terrain traps.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 9th, 2021 4:00PM
