Avalanche Forecast
Regions: Banff Yoho Kootenay, Field, Lake Louise, Little Yoho, West Side 93N.
Great skiing continues!
Storm snow amounts over the past 48 hrs range from 10 to 20 cm depending on the region and convective activity.
With broken skies forecast for Sunday, the sun could increase the hazard later in the day. Start and finish early!
The more sun, snow, and wind; the more the hazard will increase.
Confidence
Moderate
Avalanche Summary
A few small wind and storm slabs up to size 1.5 were reported during avalanche control at the local ski areas Saturday.
Natural avalanche activity was limited on Saturday, with some dry loose sluffing in steep terrain. There was evidence of a more widespread dry loose and storm slab cycle up to size 2 in the alpine during the storm.
Snowpack Summary
Up to 20 cm of storm snow (depending on convective activity) over old sun crusts on solar aspects, with new solar crusts forming. On polar aspects this storm snow may sit over a layer of stellars/spotty surface hoar crystals which is worth montioring.
In shallow snowpack areas on northerly alpine aspects where the midpack is thinner/weaker, the Feb 3 facet/crust layer and the basal facets/depth hoar remain possible to trigger.
Deeper snowpack areas have few concerns.
Weather Summary
Saturday night and Sunday:
Freezing levels to valley bottom overnight. Scattered flurries taper off through the day Sunday, as an upper trough leaves the region. Freezing levels will rise above valley bottom to 1900 m. Light to moderate westerly ridgetop winds.
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Terrain and Travel Advice
- Be alert to conditions that change with elevation and sun exposure.
- Rocks will heat up with daytime warming and may become trigger points for loose wet avalanches
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Avalanche Problems
Loose Wet
As we head into April the sun will come with more "punch". Broken skies on Sunday may result in wet loose avalanches in the afternoon especially on steep solar aspects and in rocky terrain.
Recent storm snow could also form a cohesive storm slab and become reactive on buried crusts.
Aspects: East, South East, South, South West, West.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1 - 1.5
Wind Slabs
Wind/storm slabs may be present on ridgetop and cross-loaded features, with failures on the interface below the recent storm snow. Monitor this interface carefully in steep terrain.
Dry loose avalanches out of steep terrain could also present issues in confined terrain features.
Aspects: North, North East, East, West, North West.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 1 - 2
Persistent Slabs
The Feb 3 crust/facet interface is down 80-110 cm. While we have not seen this fail in deep snowpack areas, there have been several recent skier-triggered slabs in thinner areas east of the divide. All of the recent avalanches that initiated on this layer stepped down to the basal facets / ground.
Aspects: North, North East, North West.
Elevations: Alpine.
Likelihood: Unlikely - Possible
Expected Size: 2 - 3