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Avalanche Forecast

Archived

Feb 25th, 2023–Feb 26th, 2023

Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.

Regions

North Rockies, Kakwa, McGregor, Pine Pass, Tumbler.

New wind slabs are expected to form on Saturday night and will be reactive to human triggering on Sunday. Seek out wind-sheltered terrain at lower elevations for the best riding and safest conditions.

Confidence

Moderate

Avalanche Summary

No new avalanches were observed on Thursday or Friday.

Earlier in the week there was evidence of deep persistent slab activity that likely occurred during last weekend's storm with avalanches up to size 3.5. While we currently expect the deep weak layer to be dormant, riders should continue to avoid steep, thin, rocky slopes where triggering a deep persistent avalanche would be most likely, particularly near alpine ridgelines.

Looking forward, we anticipate that new wind slabs will form Saturday night which will be sensitive to human triggering on Sunday.

Snowpack Summary

The new snowfall will arrive with strong southwest wind Saturday night, forming new wind slabs in wind-exposed terrain. The snow will overlie older wind slabs that formed between Tuesday and Friday from strong northeast wind. This means that wind slabs may be found on all aspects.

The middle of the snowpack is generally strong.

A weak layer of large and weak facets is found near the base of the snowpack. The layer is currently dormant, except perhaps in very steep alpine terrain that is inherently shallow. Riders should continue to avoid thin, rocky terrain where the likelihood of triggering this layer is increased.

Weather Summary

Saturday Night

Snowfall 5-15 cm, moderate to strong S-SW wind, treeline low around -20 °C.

Sunday

Snow flurries in the morning 1-3 cm, light to moderate SW-W wind, treeline high around -14 °C.

Monday

Mainly cloudy with light flurries, light to moderate SW wind, treeline high around -14 °C.

Tuesday

Mainly cloudy with light flurries, light SE wind, treeline high around -12 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Expect slab conditions to change drastically as you move into wind exposed terrain.
  • Recent wind has varied in direction so watch for wind slabs on all aspects.
  • Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
  • Avoid shallow, rocky areas where the snowpack transitions from thick to thin.

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.