Avalanche Forecast
Regions: Banff, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Sunshine, West Side 93N.
Despite the lack of avalanche activity over past two days don't forget about the persistent layers in the mid and lower pack. Conservative terrain choices are still advised.
Confidence
Moderate
Avalanche Summary
Several wet loose avalanches up to size 2 have been reported out of steep solar aspects over the past two days. On Tuesday, there was a deep persistent slab reported on Observation peak and Sunshine patrol reported observing two size 2.5 deep slabs in the surrounding backcountry. .
Snowpack Summary
Surface sun crusts exist to ridgetop on solar aspects and to 2000 m on shady aspects. The middle of the snowpack holds several crust layers that has produced numerous natural slab avalanches over the past 10 days. The base of the snowpack is weak, unconsolidated depth hoar in almost all areas.
Weather Summary
Friday - A trough of low pressure over the Alberta Rockies will produce cloudy skies and scattered flurries that will increase through the afternoon. Accumulations in the 1-5 cm range. Ridge-top winds will be light and the freezing levels only expected to rise to 1300 m.
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.
Avalanche Problems
Deep Persistent Slabs
The weak depth hoar at the bottom of the snowpack inspires little confidence. Multiple parties have remotely triggered large slabs from thin areas in the snowpack. 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.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 2 - 4
Persistent Slabs
Three persistent weak layers formed in January are down 40-110 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: Unlikely - Possible
Expected Size: 1.5 - 3