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 Wind Slabs and Deep Persistent Slabs.
wlewis,
Avalanche Canada
Watch for wind slabs forming at higher elevations.
Continue to avoid wind affected, thin and rocky terrain as the lower snowpack remains weak.
Summary
Confidence
Moderate
Avalanche Summary
No activity on the deeply buried weak layers has been reported this week. Kananaskis Country and the central Rockies continue to report deep persistent avalanches, including a size 3 natural on the 28th of March in Highwood Pass associated with warm temperatures and sun.
Thin and rocky terrain features in the upper treeline and alpine should still be avoided.
Snowpack Summary
Light accumulations of storm snow will form deeper deposits on north and east facing slopes at treeline and above. New snow will sit over previous wind affected surfaces at higher elevations on shaded aspects, faceted snow and surface hoar in sheltered areas, and over a melt freeze crust on south facing slopes and at low elevations.
The mid snowpack holds several persistent weak layers including layers of surface hoar in wind-sheltered terrain and sun crusts on south facing slopes. Activity on these layers has tapered off, but they may remain triggerable in isolated features.
The lower snowpack is made up of a widespread layer of large, weak basal facets and depth hoar in some areas, which produced large avalanches in the Elk Valley and the Purcells last week. Kananaskis Country reports continued avalanche activity on this layer. Avoid thin and rocky areas where this weak layer will sit closer to the surface.
Weather Summary
Friday Night
Mostly cloudy with flurries delivering up to 5 cm of snow. Light southerly wind gusting 40 km/h. Freezing levels remain around 1000 m.
Saturday
Cloudy with sunny periods possible in the afternoon. Light snowfall brings 5-10 cm. Light southwesterly wind gusting 40 km/h. Freezing level rises to 1500 m. Alpine temperatures of -5 °C.
Sunday
Cloudy with up to 5 cm of snow. Light southwest winds. Freezing levels around 1300 m, alpine highs of -7 °C.
Monday
A mix of sun and cloud with light and variable winds. Up to 5 cm snowfall possible in the east.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
Problems
Wind Slabs
Wind slabs may exist where new snow is available for transport by southwest winds. Watch for reactivity on north and east facing slopes.
Small wind slabs have the potential to step down to deeper weaknesses within the snowpack.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
The base of the snowpack remains very weak. Very large human-triggered avalanches are possible at treeline and above. Avoid thin, rocky start zones and shallow areas with variable snowpack depths. Weak layers are most triggerable here as they sit closer to the surface of the snowpack.
Deep persistent avalanches are challenging to predict. This layer can suddenly become active again, typically when there is rapid change or stress to the snowpack - sudden warming, heavy snow or rainfall, or heavy loads eg. cornice fall.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Apr 1st, 2023 4:00PM
