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Avalanche Forecast

Mar 26th, 2016–Mar 27th, 2016
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
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
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

Regions: South Columbia.

Triggering lingering storm slabs and fresh wind slabs is possible on Sunday, mainly from steep, north-facing alpine terrain. 

Confidence

High

Weather Forecast

SUNDAY: Periods of snow – around 10 cm. The freezing level is around 1400-1500 m. Winds are moderate from the W-SW. MONDAY: A mix of sun and cloud. The freezing level climbs to 1800-2000 m and winds ease to light. TUESDAY: Mainly sunny. The freezing level is around 2000 m and winds are light.

Avalanche Summary

On Friday there was one report of a very large (size 4) persistent slab on a large south-facing slope that was triggered by new snow loading. This avalanche likely failed on the late February interface. There were also numerous reports of natural storm slabs up to size 2.5, a few natural cornice falls, and several skier triggered slabs up to size 1.5. The majority of recent avalanches occurred on northerly aspects, but there were a few on south-facing alpine slopes as well.

Snowpack Summary

New storm slabs have developed above a mix of surfaces, including crusts on solar aspects, moist snow up to treeline, and dry snow or recent wind slabs in the alpine on shaded aspects. Cornices continue to be described as large and fragile. The late February persistent weak layer is an aspect dependant mix of surface hoar, facets and/or a thick crust down around 60 to 110 cm below the snow surface. Commercial operators continue to see hard sudden planar results in snowpack tests, which suggests that wide fracture propagations are possible. New storm loading above the buried persistent weak layer may increase the likelihood of triggering large avalanches. Expect loose wet avalanches and natural cornice falls during periods of strong solar radiation and/or daytime warming.

Avalanche Problems

Storm Slabs

Fresh storm slabs may be sensitive to rider triggering, especially in steep wind-loaded terrain.
Be alert to conditions that change with elevation.>Avoid freshly wind loaded features.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 3

Cornices

Cornices are an ongoing concern and should be treated with respect. Failing cornices have potential to trigger stubborn persistent weaknesses.
Extra caution needed around cornices with current conditions.>Do not travel on slopes that are exposed to cornices overhead.>

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 2 - 5

Persistent Slabs

The persistent weak layer of buried surface hoar, facets, and crusts is buried down close to a metre. This has become a low probability of triggering, but high consequence of large avalanche problem.
Avoid slopes with glide cracks.>Choose well supported terrain without convexities.>Use conservative route selection, stick to moderate angled terrain with low consequence.>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

Expected Size: 3 - 6