Avalanche Forecast
Regions: Little Yoho.
WARMING is expected Tuesday through Wednesday. Expect existing slabs to become more sensitive to triggering.
Avalanche control is planned Tuesday on the Sunshine Ski Area Access Road:
Both the Eagle and Bourgeau Closure Zones are in effect Tuesday.
Weather Forecast
A Pacific system will pass the region well to the north Tuesday, Wednesday. Tuesday the system will produce moderate W to NW winds that will increase to strong as freezing levels approach 2500m under thin cloud. A weak freeze may occur Tues night. Winds shift SW Wed and temps rise further ahead of a cold front Wed arriving Wed evening.
Snowpack Summary
Last week west winds brought 20-50 cm of snow and formed wind slabs in alpine and isolated treeline terrain. These slabs were buried Saturday by 5-15cm that again arrived with gusty W winds that formed small soft wind slabs. On Solar aspects several buried crusts are found 30 to 80 cm deep, Temperature crust up to 1800m is buried 50-60 cm deep
Avalanche Summary
No new activity reported Monday. Explosive control in Kootenay Park on Thursday produced unexpectedly large avalanches at low elevations. On Sunday, Bourgeau-Left waterfall (next to Sunshine gondola) released a large natural avalanche that ran over the waterfall and hit Healy Creek. This may have been triggered by a cornice or strong solar effect.
Confidence
Timing, track, or intensity of incoming weather system is uncertain on Tuesday
Avalanche Problems
Wind Slabs
Last week's slabs are 30-50cm thick but are likely to only be reactive in steep features. Sunday's new slabs are thin, soft and isolated to immediate lees but will be sensitive. Expect all of these slabs to become more reactive with warming.
- Pay attention to cornices which may fail as they are heated and could trigger larger avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 2
Persistent Slabs
Buried crust/facet layers exist in the upper snowpack on solar aspects and all aspects below 1800m. As the slabs overlying all of these crusts becomes heated, they will become much more sensitive to triggering. Wet slab activity may become possible.
- Be aware of the potential for wide propagations.
- Avoid travel on slopes where a crust is buried once the surface snow has become moist.
Aspects: South East, South, South West, West.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1.5 - 3
Loose Wet
As freezing levels rise, expect loose wet sluffs to become active first in lower elevation steep terrain, then progress higher. Depending on cloud cover and solar inputs, this may be intensified on steep solar slopes and solar cliffy terrain.
- If triggered the loose wet sluffs may step down to deeper layers resulting in large avalanches.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood: Likely
Expected Size: 1 - 2