Avalanche Forecast
Issued: Mar 14th, 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.
GS,
Avalanche Canada
All climbs on Mt Stephen are closed to climbing on Wednesday, March 15 as CP Rail is doing avalanche control.
The storm is over and the sky is clearing, but the snowpack is weak in this region and continued natural avalanches are expected on solar aspects over the next 24-48 hours. The winds are forecast to be light, but even subtle changes to the surface slab properties may release avalanches. Continue to avoid large avalanche terrain features and avoid climbing in gullies with any exposure to the sun.
Summary
Confidence
Moderate
Avalanche Summary
Observations of the recent avalanche cycle are starting to come in on Tuesday, most notably a large, deep size 3 on Puzzle Peak that crossed the standard uptrack (solar triggered probably). The Lake Louise ski area continues to trigger deep (ground) avalanches from their explosive control work. Finally, a large natural avalanche in Kananaskis Country ran over some ice climbs on Mt. Kidd.
Snowpack Summary
3-day storm totals are Sunshine 15 cm, Simpson, 13 cm, Stanley 11 cm, Bosworth 22 cm and Bow Summit 31 cm.
This new snow has fallen on a freshly buried (March 12) layer of surface hoar, facets and sun crust and will not bond well. Strong SW winds near the storm's end have created windslabs sitting above this weak layer. Expect this layer to fail with solar inputs. The midpack comprises various Jan crust layers that are now down 60-100 cm. The weak Nov. 16 basal facet layer is down 50-120 cm producing sudden results in snowpack tests.
Weather Summary
A quiet few days of weather ahead as a ridge of high pressure builds over the region keeping skies partly cloudy with no new snow expected and light winds over the next several days. Temperatures will remain cool, with overnight lows hitting -20 in the alpine and daytime highs reaching -5 or warmer in the valley bottoms.
For a more detailed forecast click here.
Terrain and Travel Advice
- Uncertainty is best managed through conservative terrain choices at this time.
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
Problems
Storm Slabs
Surface snow from the past few days of storms will settle into a slab over a new weak layer buried on March 12. Avalanches may release from solar inputs when the sky clears on Wed or Thurs this week. These avalanches may start small but then trigger a deeper layer and become large.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
Weak depth hoar at the bottom of the snowpack inspires little confidence and will wake up with each new storm or warming event. Avoid big terrain features and be especially cautious in thin or rocky areas, where triggering is more likely. Cornice failures or smaller avalanches may act as a trigger for this layer so careful consideration of the slopes above your head is wise.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Three persistent weak layers formed in January are down 60-110 cm. Buried sun crusts on steep solar slopes present the greatest concern for triggering, however, weak facets and isolated surface hoar can be found on the same interfaces on shaded aspects.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 15th, 2023 4:00PM
