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.
LP,
Avalanche Canada
Continued natural avalanches are expected on solar aspects over the next 24-48 hours, and cornice failures may continue to trigger the deep persistent layer on the lee aspects. 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 Wednesday, a large deep size 3 on Pilot Mountain and over the Sacre Blue ice climb on Mt. Rundle was reported. On Tuesday, a notable large, deep size 3 on Puzzle Peak crossed the standard up track (cornice triggered probably). The Lake Louise ski area reported whumphing and shooting cracks at and below treeline. Finally, a large natural avalanche in Kananaskis Country ran over some ice climbs on Mt. Kidd.
Snowpack Summary
3-day storm totals Sunshine 21 cm, Simpson, 13 cm, Stanley 12 cm, Bosworth 25 cm and Bow Summit 34 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
Sunny skies are forecasted for Thursday with afternoon cloudy periods. Light morning N-NW winds will ease to very light westerly. Freezing levels between 1300 to 1500 m with alpine temperatures ranging between -10 to -15C. Friday & Saturday, clear skies continue, daytime freezing levels climb to 1800 m with warmer alpine temperatures ranging between -5 and -10 C.
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 will settle into a slab over a new weak layer buried on March 12. We are currently assessing this interface throughout the region. Avalanches may release from solar inputs Thursday. 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
With the forecasted solar input and warm temperatures, we may see more cornice failures and or smaller avalanches triggering this deep layer. Give careful consideration to the slopes overhead as large avalanches may run well into the runout zone or into lower-angle terrain. Avoid big terrain features and be especially cautious in thin or rocky areas, where triggering is more likely. The weak depth hoar at the bottom of the snowpack inspires little confidence and will continue to wake up with each new storm or warming event.
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 16th, 2023 4:00PM
