Avalanche Forecast

Issued: Nov 23rd, 2013 8:25AM

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

Avalanche Canada ghelgeson, Avalanche Canada

Please note this bulletin is based on limited information. If you have been out and have observations, please send them to forecaster@avalanche.ca

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

Synopsis: The ridge of high pressure continues to strengthen, driving an inversion pattern across the region that should persist through the forecast period. Sunday: Cloudy with sunny periods. Precipitation: Nil. Alpine temperature: High 1 Light ridge wind. Freezing level: 2400m Monday: Sunny with cloudy periods. Precipitation: Nil. Alpine temperatures: Low -4 High -3 Light ridge wind. Freezing level: 1500 m. Tuesday: Cloudy with sunny periods. Precipitation: Nil. Alpine temperatures: Low 0 High 0  Ridge wind southwest 20 gusting to 65 km/h. Freezing level: 2300 m.

Avalanche Summary

Avalanche activity was reported in pockets of deeper snow from Monday (18th) and Tuesday (19th) in both western and eastern areas of the region. Activity appears to have tapered off. Recent slope tests have produced results only in isolated pockets of wind slab on steep convex rolls.

Snowpack Summary

Treeline snowpack depths in sheltered areas vary between approximately 40-80 cm. In the alpine, coverage is highly variable due to recent high winds. A crust or significant density change may exist around 40 cm below the surface. This has been reported to have weak faceted crystals above and below, and produces sudden "pop" results in compression tests. Below this near the base of the snowpack, an earlier crust buried in October lies close to the ground. This layer may still be of concern on isolated smooth terrain features that have not seen avalanche activity.

Problems

Wind Slabs

An icon showing Wind Slabs
Wind slabs are widespread and will likely remain sensitive to human triggering, especially on steep convex slopes near ridge crest.
Use ridges or ribs to avoid pockets of wind loaded snow.>Avoid freshly wind loaded features.>Use extra caution in lee areas in the alpine. Recent wind loading has created wind slabs.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs
Weak layers deep in the snowpack may become more sensitive to both natural and human triggered avalanches  as temperatures increase.
Avoid exposure to overhead avalanche terrain as temperatures increase.>Be aware of the potential for large deep avalanches.>Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.>

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 4

Loose Wet

An icon showing Loose Wet
Loose wet avalanches may be a concern as cold snow is exposed to warm temperatures for the first time Sunday.
Avoid terrain traps where the consequences of small avalanches may be more severe.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Nov 24th, 2013 2:00PM