Avalanche Forecast
Issued: Apr 1st, 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 small but reactive wind slabs as you gain elevation.
Small wind slabs may trigger larger avalanches on deeply buried weak layers. Continue to avoid wind affected, thin and rocky terrain.
Summary
Confidence
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
New snow and wind are forming wind slabs at higher elevations, over a melt freeze crust (on all aspects at low elevations, and on sun affected slopes to mountain top). On north facing slopes at treeline and alpine, new snow sits over previously wind affected surfaces.
The mid snowpack holds several persistent weak layers including layers of surface hoar in wind-sheltered terrain and sun crusts on south facing slopes. No recent activity has occurred on these layers, 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
Saturday
Cloudy. Light flurries continue overnight. Light southwesterly wind gusting moderate. Freezing level drops to 500 m.
Sunday
Cloudy with flurries delivering a few cm of snow, heaviest close to the Alberta border with up to 5 cm. Light southwest winds. Freezing levels around 1300 m, alpine highs of -7 °C.
Monday
Mostly cloudy with light easterly winds. Up to 5 cm snowfall possible in the east. Freezing levels reach 1100 m.
Tuesday
Clearing skies with 1300 m freezing levels. Light easterly winds.
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
Small wind slabs exist at treeline and above, from new snow and southwest winds. Watch for reactivity on north and east facing slopes near ridgelines.
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.
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 2nd, 2023 4:00PM
