Avalanche Forecast
Issued: Mar 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.
bchristie,
Avalanche Canada
The avalanche danger will increase as the storm snow piles up. Stick to mellow terrain, and avoid travelling under large slopes, especially if you see signs of instability like shooting cracks or fresh avalanches.
Summary
Confidence
Moderate
Avalanche Summary
On Thursday, north of Revelstoke, a large (size 2), naturally triggered, deep persistent slab avalanche was reported. It occured on a steep, north facing slope in the alpine, below a large cliff face, and it is possible that it was triggered by a cornice fall.
On Wednesday, northwest of Revelstoke, explosive avalanche control triggered a few small cornice and wind slab avalanches on north aspects in the alpine.
Expect natural and human triggered avalanches to be more likely as new storm snow piles up overnight on Friday, and through the day Saturday.
Snowpack Summary
10-25 cm of new snow sits over a thin crust on steep slopes facing the sun right up into the alpine. Moderate southwest wind may be forming deeper deposits of snow on leeward slopes. On high, north-facing terrain, wind slabs may sit over facets and surface hoar.
The mid-snowpack is generally strong but the lower snowpack is a different story. The November facets are still prominent at the base of the snowpack. This layer remains a concern in rocky, shallow, or thin to thick snowpack areas at treeline and above.
Weather Summary
Friday Night
Cloudy. 2-5 cm of snow expected, up to 15 cm in some areas. Light to moderate southwest ridgetop wind. Freezing level around 900 m. Treeline high around -5°C.
Saturday
Cloudy. 5-10 cm of snow expected. Light southwest ridgetop wind, possible periods of moderate in the morning. Freezing level around 1200m.
Sunday
Mostly cloudy. 0-2 cm of snow expected. Very light southwest ridgetop wind. Freezing level at valley bottom overnight, rising to around 1300m.
Monday
Mostly cloudy. Possible trace of snow expected. Up to 5cm on the far west edge of the forecast area. Freezing level at valley bottom overnight, rising to around 1300m.
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.
- Continue to make conservative terrain choices while the storm snow settles and stabilizes.
- Keep in mind the crust offers an excellent bed surface for avalanches.
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
Problems
Storm Slabs
The current storm could result in up to 25 cm of new snow in some areas. The incoming storm is forecasted to drop variable amounts of snow across the region, with localized hot spots. If you are seeing lower snowfall amounts in your area, you may see less storm slab avalanche activity.
Moderate southwest wind may be forming deeper, more reactive deposits of snow on leeward slopes.
Due to the recent warm and sunny weather, a thin crust formed on steep slopes facing the sun right up into the alpine. Avalanches are more likely on slopes where the new snow is sitting on top of this crust.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
A weak layer of facets exists near the base of the snowpack. The likelihood of human triggering is low given the layer's depth. Suspect terrain for human triggering includes steep, shallow, and rocky terrain where the snowpack transitions from thin to thick.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Apr 1st, 2023 4:00PM
