Avalanche Forecast
Issued: Feb 19th, 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.
zryan,
Avalanche Canada
The south of the region will be the hotspot on Monday as heavy snowfall forms increasingly large and reactive storm slabs.
Be prepared to dial back into more conservative terrain as new snow accumulates. Be especially cautious in shallow snowpack areas where triggering a deep persistent slab remains possible.
Summary
Confidence
Moderate
Avalanche Summary
Looking forward to Monday, we expect avalanche danger to increase throughout the day as heavy snowfall forms increasingly large and reactive storm slabs.
No significant avalanches were reported in the past few days but observations have been limited.
One natural size two deep persistent slab was reported last Thursday in the northern part of the region. It was on a northeast aspect in the alpine. Deep persistent slab avalanches like this one continue to be reported at least once a week in shallow snowpack areas.
Snowpack Summary
Up to 20 cm of new snow can be expected by the end of the day on Monday. This new snow overlies last week's storm snow and wind-affected surfaces in exposed areas. Windward slopes are generally scoured or pressed with older wind slabs found on north and east aspects.
Several layers of facets, crusts or surface hoar can be found in the top 1.5 meters of the snowpack.
In shallow snowpack areas layers of facets from November and December are near the bottom of the snowpack and have likely been responsible for some large avalanches.
Weather Summary
Sunday night
Cloudy with clear periods and isolated flurries. Alpine temperatures drop to a low of -7 °C. Ridge wind west 20 km/h gusting to 50 km/h. Freezing level at valley bottom.
Monday
Cloudy with snowfall, heavy at times, 10-20 cm of accumulation. Alpine temperatures reach a high of -6 °C. Ridge wind east 20-35 km/h. Freezing level 700 metres.
Tuesday
A mix of sun and cloud with isolated flurries. Alpine temperatures reach a high of -11 °C. Ridge wind northeast 20-40 km/h. Freezing level at valley bottom.
Wednesday
Sunny Alpine temperatures reach a high of -20 °C. Ridge wind northeast 20-40 km/h. Freezing level at valley bottom.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Watch for changing conditions today, storm slabs may become increasingly reactive.
- Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
- As the storm slab problem gets trickier, the easy solution is to choose more conservative terrain.
- Avoid areas with a thin or variable snowpack.
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
Problems
Storm Slabs
Storm slabs will increase in size and reactivity throughout the day as snowfall intensifies.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
Over the past few weeks we have recieved reports of large deep persistent slab avalanches. Triggering an avalanche on deeply buried facets is unlikely but very consequential. Avoid shallow, steep and rocky start zones at treeline and above where triggering a deep persistent slab could be possible.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 20th, 2023 4:00PM
