Avalanche Forecast
Issued: Jan 31st, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Deep Persistent Slabs.
swerner,
Avalanche Canada
Updated at 6:25 AM Pacific on Wednesday: Less snow is falling compared to yesterday's forecast, but dangerous avalanche conditions still exist as fresh storm slabs are building. A small avalanche could step down to deeper weak layers.
Summary
Confidence
Moderate
Avalanche Summary
No new avalanches were observed on Monday. Many wind slab avalanches were triggered by riders and naturally last Saturday. They occurred on all aspects.
Looking forward, riders may trigger storm and wind slab avalanches in wind-exposed terrain as we receive new snow and strong wind throught he forecast period. Smaller avalanches could step down to the facets near the base of the snowpack, producing very large avalanches. See more on the potential of triggering deeper weak layers Forecasters' Blog.
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Snowpack Summary
Up to 20 cm of fresh low-density snow may form new wind slabs in lee terrain features in wind-exposed terrain. The snow will rest on previously wind-affected snow. A melt-freeze crust is found near the snow surface on sun-exposed slopes and everywhere below 1600 m.
Several crust/facet/surface hoar layers exist in the upper and middle portions of the snowpack. Recent observations suggest these layers are not as concerning as in neighbouring regions.
The most concerning layer is at the base of the snowpack from large and weak facets formed in November. This layer is widespread and most likely problematic in steep, rocky alpine terrain.
Weather Summary
Tuesday Night
Cloudy new snow 10- 15 cm. Strong northwest wind at the ridgetop. Treeline temperatures steady -12 °C.
Wednesday
Cloudy with snowfall, accumulation 10-20 cm with local enhancements expected. Ridgetop wind moderate from the West and treeline temperature -12 °C.
ThursdayCloudy with snowfall, accumulation 10 to 20 cm. Ridgetop wind light to moderate from the southwest. Treeline temperature -10 °C.
FridayCloudy with snowfall, accumulation 5 to 20 cm. Ridgetop wind moderate from the southwest and treeline temperatures warming to -5 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Storm slab size and sensitivity to triggering will likely increase through the day.
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- Uncertainty is best managed through conservative terrain choices at this time.
Problems
Storm Slabs
New snow and strong wind will likely build reactive storm slabs through the forecast period. Storm and wind slab avalanches may step-down to deeper weak layers initiating large and destructive avalanches.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
A layer of large and weak facets sits near the base of the snowpack. This layer is most prominent in upper treeline and lower alpine elevations. As snow accumulates, the likelihood of natural and human-triggered avalanches increases. Riders are most likely to trigger an avalanche on this layer in steep, shallow terrain, or by triggering a smaller avalanche that could step down to this layer.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Feb 1st, 2023 4:00PM
