Avalanche Forecast
Regions: Little Yoho.
Avalanche control on Mts. Bourgeau, Whymper, Bosworth, Stephen and Wardle Friday. No outdoor activities there. Forecast clearing skies means high solar impact. Expect large avalanches in the region.
Weather Forecast
Friday looks like a crux day with freezing levels to 2500-2600m, light winds and a good chance this cloud will clear off producing high solar input. Saturday will see increased cloud and a switch to a westerly flow with moderate W winds in the alpine and freezing levels up to 2500m.
Snowpack Summary
The snowpack is in transition between winter and spring, and is a poor example of both. There was a 2-4cm crust (thinner BTL) on solar aspects to ridgetop with moist snow underneath Thursday AM, and this crust is breaking down during the day. Dry powder snow only exists on high North facing terrain
Avalanche Summary
A flight from the Wapta to Banff showed solar induced loose,wet avalanches to size 2 in the last 24 hours, and some deeper releases to size 2.5, mainly below steep cliffs in the alpine. Reports of many solar induced natural avalanches in Kootenay today to size 3.5 where the sun has been out all day. Many of these are stepping to ground.
Confidence
Timing or intensity of solar radiation is uncertain on Friday
Avalanche Problems
Loose Wet
Wet snow avalanches will be running in most steep gully features, near cliff bands and on steep slopes.
- Minimize exposure when the solar radiation is strong, especially if snow is moist or wet.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Very Likely
Expected Size: 1 - 2
Persistent Slabs
Several buried suncrusts exist in the upper snowpack, and slab avalanches can be expected on these crusts as the heat penetrates the snowpack over the next few days.
- Travel early before the heat of the day, and avoid big slopes in the afternoon.
Aspects: North, North East, East, South East.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 2 - 3
Cornices
Cornices are large. Give them a wide berth on ridge crests, as they can pull back a long way when they fail and may trigger an avalanche below. If you need to travel under cornices, move quickly but think twice if there is significant heating.
- Pay attention to overhead hazards like cornices which could easily trigger persistent slabs.
Aspects: North, North East, East, South East.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 2 - 3