Avalanche Forecast
Issued: Mar 12th, 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 Cornices.
lbaker,
Avalanche Canada
Warm temperatures, new snow and strong winds will create dangerous avalanche conditions on Monday.
Uncertainty is best managed by conservative terrain choices at this time. Avoid shallow areas where triggering the deep persistent weak layer is more likely.
Summary
Confidence
Avalanche Summary
On Saturday, a few cornice failures were observed in the alpine during a brief period of direct sun. Observed failures did not trigger the slope beneath them. Check out the MIN report for more details.
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
Accumulating flurries on Monday will cover a variety of surfaces including small pockets of wind slab on exposed south and west slopes, hard wind-affected surfaces in open areas, a sun crust on steep solar aspects, and facetted snow in sheltered areas.
In the Purcells, several weak layers from Jan and Feb can be found down 50 to 120 cm however they are showing signs of strengthening. The mid-snowpack is generally well-settled.
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
Sunday Night
Cloudy with isolated flurries, 2-5 cm accumulation. Alpine temperatures reach a low of -5 °C. Ridge wind 25 to 40 km/h from the southwest. Freezing levels remain at 1400 meters.
Monday
Cloudy with mixed precipitation The Purcells will see 10-12 cm of new snow while the Rockies see 5- 8 cm. Alpine temperatures reach a high of -1 °C. Ridge wind 30 to 50 km/h from the southwest. Freezing levels rise to 1800 meters.
Overnight flurries continue bringing an additional 10 cm of new snow to the Purcells and 12-17 cm to the Rockies. Freezing levels remain around 1700 m overnight.
Tuesday
A mix of sun and cloud with isolated flurries. Alpine temperatures reach a high of -5 °C. Ridge wind 15 to 30 km/h from the southwest. Freezing levels 1300 meters.
Wednesday
A mix of sun and cloud with isolated flurries. Alpine temperatures reach a high of -2 °C. Ridge wind 10 to 20 km/h from the west. Freezing levels rise to 1500 meters.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Watch for fresh storm slabs building throughout the day.
- In times of uncertainty conservative terrain choices are our best defense.
- Avoid rock outcroppings, convexities, and anywhere the snowpack is thin and/or variable.
- Minimize overhead exposure; avalanches triggered by warming or cornice fall may be large and destructive.
Problems
Storm Slabs
New snow, warm temperatures and strong southwest winds will form fresh reactive storm slabs on Monday. Be particularly cautious of lees at alpine and treeline. Slabs may be particularly reactive on solar slopes where they are poorly bonded to the underlying crust.
Aspects: All aspects.
Elevations: All elevations.
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
Cornices
Minimize your exposure to cornices, rising freezing levels will cause them to weaken and increase the possibility of failure. If they fail they could trigger weak layers deep in the snowpack resulting in large destructive avalanches. Give them respect and a wide berth when you are traveling under them.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Mar 13th, 2023 4:00PM
