Avalanche Forecast

Issued: Nov 24th, 2013 8:31AM

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

swerner, Avalanche Canada

Cariboos.

The forecasts are based on limited observations. Have you been playing in the mountains? Feel free to send your information to forecaster@avalanche.ca.

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

An upper ridge of high pressure will remain over the Interior regions. At higher elevations (1600-2800m) a temperature inversion will persist through Tuesday and be pushed out by Wednesday. Monday: May receive light snow amounts. Mainly cloudy. Alpine temperatures near 0 degrees. Freezing levels rising to 2500 m. Light-moderate ridgetop winds from the southwest. Tuesday: Mix of sun and cloud. Alpine temperatures -2. Freezing levels 1500 m. Light westerly ridgetop winds.Wednesday: Mix of sun and cloud. Alpine temperatures -3. Freezing levels dropping to 1200 m. Light westerly winds.

Avalanche Summary

Recently no new avalanches have been reported. However, isolated large slab avalanches may still be rider triggered, especially in areas that didn't previously avalanche.

Snowpack Summary

Snowpack depths at upper elevations sit near a metre or more. Recent storm snow seems to be settling, but wind slab problems likely exist.A surface hoar layer may exist 60-120 cm down but seems to be spotty, and drainage specific. Have you seen any?Deeper in the snowpack near the base is a melt-freeze / rain crust that formed in October. This is generally found from 80-160 cm down near the base of the snowpack. On northerly aspects a more predominant crust/ facet combo may exist and allow for wider propagations. especially in places that have smooth ground over (glacier ice, grassy slopes, rock slabs etc.)Snowpack conditions may change and deteriorate if temperatures rise in the alpine.

Problems

Wind Slabs

Wind slabs have built on lee slopes and behind terrain features. Cracking, stiff snow, and whumphing in the snowpack are direct indicators of wind slab formation.

Use caution in lee areas in the alpine. Recent wind loading have created wind slabs.>Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

The probability of triggering a persistent slab may be decreasing; however if triggered, the consequence would be high. Watch shallower, thin-spot trigger points.

Dig down to find and test weak layers before committing to a line.>Be aware of the potential for large, deep avalanches due to the presence of buried crust.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 5

Valid until: Nov 25th, 2013 2:00PM