Avalanche Forecast
Issued: Feb 26th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
zryan,
Avalanche Canada
Don't let good visibility and the desire to ride deep powder lure you into consequential terrain. Natural activity may taper but human-triggered storm slabs remain LIKELY! Sheltered and shaded terrain will offer the best and safest riding.
Treat the avalanche danger as HIGH and avoid avalanche terrain and overhead exposure during periods of strong solar radiation.
Summary
Confidence
Moderate
Avalanche Summary
Earlier in the week, numerous natural and human-triggered wind slabs (size 1-2) were reported throughout the region as strong northerly outflow winds redistributed surface snow and create stiff pockets of wind slab. These slabs occurred on a variety of aspects in the alpine all the way down to below treeline terrain.
On Sunday, numerous human-triggered storm slabs up to size 2 were reported from all aspects and elevations. Observations were limited due to visibility, but we suspect a natural cycle will have occurred in alpine terrain.
Looking forward to Monday, dangerous avalanche conditions will persist. Expect human-triggered storm slabs to be likely, especially in wind-loaded areas and on sun-exposed slopes.
For a deeper dive into conditions leading up to Saturday's storm, check out this awesome South Coast Conditions Report posted by Zenith Guides.
Snowpack Summary
Saturday night's storm brought 20-50 cm of new snow down to valley bottom. This new snow has bonded poorly to the underlying surface consisting of stiff wind slabs and near-surface facetting formed by recent wind and cold temperatures.
There are two crusts with facets sitting above, which are buried in the snowpack down 60-180cm in the alpine and treeline elevation bands. These crust/facet layers have been responsible for a few large avalanches in the past 2 weeks in the Brandywine and Pemberton Icefield areas.
The remainder of the mid and lower snowpack is well-settled, strong, and consolidated.
Weather Summary
Sunday night
Clear periods with isolated flurries. Alpine temperatures drop to a low of -12 °C. Ridge wind southwest 15-35 km/h. Freezing level at valley bottom.
Monday
A mix of sun and cloud. Alpine temperatures reach a high of -10 °C. Ridge wind light from the southwest. Freezing level 700 metres.
Tuesday
A mix of sun and cloud with isolated flurries. Alpine temperatures reach a high of -9 °C. Ridge wind light variable. Freezing level at valley bottom.
Wednesday
A mix of sun and cloud. Alpine temperatures reach a high of -11 °C. Ridge wind southwest 10-20 km/h. Freezing level at valley bottom.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Give the new snow several days to settle and stabilize before pushing into bigger terrain.
- Seek out sheltered terrain where new snow hasn't been wind-affected.
- Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.
- Brief periods of sun could quickly initiate natural avalanche activity.
Problems
Storm Slabs
Up to 50 cm of storm snow has bonded poorly to the underlying surface and may have formed a widespread storm slab problem. Deeper and more reactive deposits will exist in wind-loaded areas.
Even brief periods of sun could cause rapid settlement in the storm snow and initial natural avalanches. Avoid being on or under sun-exposed slopes.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Two weak layers consisting of a crust with small facets above buried between 50 and 180cm deep, have been responsible for a few large avalanches in the past two weeks. This problem seems to be more of an issue west of the Sea to Sky highway corridor. This layer is of greatest concern with large triggers, such as a cornice fall, or by first triggering a smaller avalanche that could step down to this interface.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 27th, 2023 4:00PM
