Avalanche Forecast
Issued: Mar 15th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs, Deep Persistent Slabs and Persistent Slabs.
lbaker,
Avalanche Canada
Watch for hazard increasing during peak daytime heating. Natural avalanches are possible and human-triggered avalanches are likely.
Avoid thin areas like rock outcroppings where you are most likely to trigger deep persistent layers.
Summary
Confidence
Avalanche Summary
On Tuesday, good visibility revealed a widespread natural avalanche cycle from within the storm. Numerous storm slab and wind slab avalanches were observed on all aspects in the alpine and at treeline, up to size 2.5. Three natural deep persistent slab avalanches were observed in the Golden area, size 2.5-3, in steep, rocky terrain at 2400m. Evidence of a size 4 natural deep persistent slab avalanche was observed in the western Purcells.
If you head out in the backcountry, let us know what you are seeing by submitting a report to the Mountain Information Network.
Snowpack Summary
15-30 cm of wind-affected storm snow overlies wind-affected snow in open areas, facetted snow in sheltered areas and a thin sun crust on steep solar slopes.
Buried surface hoar sits 70-90 cm deep in sheltered terrain features, and a thin sun crust exists at the same depth on steep south-facing terrain. Several other layers from January can also be found in the top 100cm of the snowpack.
The lower snowpack is made up of a widespread layer of large, weak basal facets and depth hoar in some areas. this weakness has been responsible for a number of recent very large, destructive avalanches and will continue to be a concern.
Weather Summary
Wednesday Night
Few clouds clear through the night. Alpine temperatures reach a low of -10 °C. Ridge wind northwest 20 km/h gusting 30 km/h. Freezing levels drop to valley bottom.
Thursday
Mix of sun and cloud. Alpine temperatures reach a high of -4 °C. Ridge wind west 15 km/h. Freezing levels rise to 1500 meters.
Friday
Mainly sunny. Alpine temperatures reach a high of -3 °C. Ridge wind southwest 20 km/h. Freezing levels rise to 1600 meters.
Saturday
Sunny. Alpine temperatures reach a high of -2 °C. Ridge wind southwest 15 km/h. Freezing levels rise to 1700 meters.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Be especially cautious as you transition into wind affected terrain.
- Be alert to conditions that change with elevation and sun exposure.
- Minimize exposure to sun-exposed slopes when the solar radiation is strong.
- Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
- Avoid areas with a thin or variable snowpack.
Problems
Storm Slabs
15-30 cm of storm snow has settled with warm temperatures into a reactive storm slab over a variety of surfaces. Be extra cautious on north and east slopes where southwest winds have built deeper pockets of storm slab.
If triggered, storm slab avalanches may step down to deeper weak layers resulting in large avalanches.
Aspects: All aspects.
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 shallow and rocky areas, where the snowpack depth is highly variable. This is a very concerning avalanche problem and should stay in your mind when traveling in the backcountry.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Numerous weak layers from January and February exist at all elevations on a variety of aspects. On shaded slopes, these layers generally present as surface hoar, and on sun-exposed slopes they present as facets and a crust.
Avalanches triggered on these layers can step down to the facets at the bottom of the snowpack resulting in a very large avalanche.
These layers can be remotely triggered. Avoid traveling below steep slopes.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 16th, 2023 4:00PM
