Avalanche Forecast

Archived

Nov 19th, 2011–Nov 20th, 2011

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

Northwest Coastal.

This bulletin is based on limited data. Local variation in conditions and danger levels are likely to exist. To produce more accurate forecasts, we need information. Please send an email to [email protected]

Confidence

Poor - Due to limited field observations

Weather Forecast

Sunday should continue to be cooler and drier in the morning. The next wave of precipitation should move on to the coast around mid-day Sunday and begin to affect the interior ranges Sunday night and into Monday. Heavy precipitation combined with strong southwest winds should dominate Tuesday. Freezing levels may rise to 1500 metres on Tuesday.

Avalanche Summary

We have a few reports of glide crack releases at lower elevations near Terrace, and a recent size 2.0 slab release near Shames in the backcountry. Wind slabs are expected to remain sensitive to human triggers throughout the forecast period.

Snowpack Summary

Total snowpack depth in most sheltered treeline areas is around 100cm to150cm. Extensive wind-transport has created highly variable snowpack depths in exposed areas at all elevations with weak wind slabs 50 to100cm thick. The mid and lower snowpack seems to be well settled and strong with an old rain crust near the ground.

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.