Avalanche Forecast

Issued: Jan 12th, 2015 8:26AM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is moderate. Known problems include Persistent Slabs.

rbuhler, Avalanche Canada

Cariboos.

Avalanche activity on the tricky mid-Dec weak layer has decreased recently but this layer should still be treated as a major hazard for the foreseeable future. Large and destructive human-triggered avalanches remain possible.

Summary

Confidence

Fair

Weather Forecast

A ridge of high pressure continues to be the dominate weather feature for the next three days. Tuesday should see a mix of sun and cloud, freezing levels climbing to around 1000m, and light-to-moderate alpine winds. On Wednesday, an above-freezing layer (AFL) of air will form over the interior. This layer is expected to sit between 1500 and 2500m elevation. Alpine winds should remain light and sky should be mostly sunny with cloudy periods. The AFL persists on Thursday but should break down by Thursday afternoon. Thursday should see a mix of sun and cloud, and alpine winds are forecast to be moderate-to-strong from the SW. The next weather system is expected for Thursday night or Friday.

Avalanche Summary

No new reports of avalanches since Saturday. On Saturday, a snowmobiler triggered a size 2 avalanche and was partially buried (YouTube video: https://www.youtube.com/watch?v=yhhAUcvXa3Q). This occurred in an opening at 1600m. It occurred on the mid-Dec weak layer down 40-50cm. Natural activity is generally not expected on Tuesday but remains possible in isolated areas, especially on sun exposed slopes. Human-triggered persistent slabs remain the main concern for the foreseeable future.

Snowpack Summary

Reports that the temperature inversion has left a crust above 1800m on most aspects in the Valemount area. Other parts of the region are reporting a thin solar crust on steep south and east aspects. Warm temps and time have helped to settle the 30 - 90cm of storm snow that fell almost a week ago. That snow rests on the mid-December surface hoar/crust persistent weak layer that continues to produce inconsistent test results. It seams to be most sensitive at and below treeline (approx: 1900m).

Problems

Persistent Slabs

A persistent weakness buried mid-December is spotty in distribution and reactivity, but remains very problematic at and just below treeline where the snowpack structure may be primed for human triggering.

Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

3 - 5

Valid until: Jan 13th, 2015 2:00PM