Archived

Avalanche Forecast

Nov 27th, 2012–Nov 28th, 2012

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

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

1: Low

The avalanche danger rating below treeline will be low

Alpine

4: High

The avalanche danger rating in the alpine will be high

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

Regions: South Coast.

Avalanche danger is set to rise with stormy weather.

Confidence

Poor - Due to limited field observations for the entire period

Weather Forecast

Wednesday: Snow with 5-15cm of accumulation, freezing levels around 1700m, and moderate to strong southerly winds. Thursday: Snow with 20-30cm of accumulation, freezing levels around 1500m, and strong southerly winds. Friday: Continued snowfall with another 15-20cm, freezing levels remaining at 1500m, and extreme southerly winds.

Avalanche Summary

Check out Wayne Flann's Avalanche Blog for a photo of a recent large avalanche off the north face of Mt. Currie. After a brief lull, avalanche activity will likely pick up again with forecast wind and snow.

Snowpack Summary

The snow surface consists of large surface hoar, a thin sun crust, surface facets, moist snow, or preserved storm snow depending on elevation, sun and wind exposure, slope angle, time of day, and aspect; all of which could become weak layers once buried by a sufficiently cohesive slab. The main snowpack feature is a rain crust buried early November and now down around 60-80cm at treeline. A weak layer of facets sitting on top of this crust shows "sudden" fracture character and the ability to propagate into large avalanches if triggered, but because this weakness is so close to the ground in most areas, associated avalanche activity will likely be limited to slopes with smooth ground cover (e.g. scree slopes, rock slabs, summer firn, glaciers, etc.). For more information check out the telemarktips.com forum, the Mountain Conditions Report, and Wayne Flann's Avalanche Blog.

Avalanche Problems

Wind Slabs

Expect to find weak wind slabs below ridgecrests, behind terrain features, and in cross-loaded gullies. Natural avalanche activity is possible with heavy loading from snow and wind, and human triggering is likely, especially on steep convex slopes.

Assess start zones carefully and use safe travel techniques.>Avoid freshly wind loaded features.>

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 3

Persistent Slabs

Slopes with smooth ground cover and reloaded bed surfaces. Prone to remote triggering and step down avalanches. Typical trigger points include thin rocky areas. May be difficult to trigger, but often very large with serious consequences.

Avoid convexities or areas with a thin or variable snowpack.>Be aware of thin areas that may propagate to deeper instabilites.>Whumpfing, shooting cracks and recent avalanches are all strong indicators of an unstable snowpack.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 2 - 5