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Avalanche Forecast

Jan 28th, 2016–Jan 29th, 2016
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low

Regions: Sea To Sky.

Conservative terrain selection is still required while the snowpack adjusts to heavy storm loading from the last few days.

Confidence

Moderate - Freezing levels are uncertain

Weather Forecast

On Friday expect 5-15cm on new snow, strong southwest winds and freezing levels at about 1000m. On Saturday and Sunday, the region will see another 5cm of new snow each day with freezing levels hovering around 800m. Winds for Saturday will be mainly moderate and southwesterly, switching to light and northerly on Sunday.

Avalanche Summary

In recent days, backcountry avalanche observations have been extremely limited, mostly due to stormy weather. That said, I'm sure there was a widespread natural avalanche cycle on Thursday in response to heavy storm loading. Forecast cooling should help gradually reduce natural avalanche activity. But, for the short term storm slabs will likely remain sensitive to light loads, while potential remains for very large persistent slab avalanche activity.

Snowpack Summary

On Wednesday night and Thursday morning, heavy snowfall and strong winds continued to form deep and dense storm slabs in high elevation terrain and cause substantial cornice growth. At treeline and below, rain fell and further saturated the snowpack. The snow line fluctuated a great deal during the storm which dropped around 80mm of precipitation throughout the region.Where it still exists, the mid-January surface hoar layer is between 100 and 180 cm below the surface. The hope is the combination of heavy storm loading and warm temperatures has flushed out this weak layer in most areas, but that remains to be seen. In the wake of the storm, there will be a lot of uncertainty regarding the reactivity and distribution of this destructive persistent avalanche problem, especially at high elevations in the north of the region where continued reactivity at this interface has been observed. Additionally, the snowpack will require time to adjust to the stress of heavy storm loading. A very conservative approach to mountain travel is still required.

Avalanche Problems

Storm Slabs

Continued snowfall and strong winds on Friday will contribute to an ongoing storm slab problem. Watch for increased triggering in wind-exposed terrain.
Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Be alert to conditions that change with elevation.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 3

Persistent Slabs

Deep and destructive persistent slab avalanches may remain a concern in high elevation terrain (especially in the north of the region) as the snowpack adjusts to recent heavy storm loading.
Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 3 - 5

Cornices

Recent storms have formed very large and unsupported cornices, and at least one person has taken an unexpected ride. Use extra caution around ridge crests in the alpine.
Give cornices a wide berth when travelling on or below ridges.>

Aspects: North, North East, East, South East.

Elevations: Alpine.

Likelihood: Possible

Expected Size: 1 - 3