Archived

Avalanche Forecast

Dec 29th, 2017–Dec 30th, 2017

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

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

2: Moderate

The avalanche danger rating in the alpine will be moderate

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

2: Moderate

The avalanche danger rating in the alpine will be moderate

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

Regions: Banff Yoho Kootenay.

The danger rating has risen due to loose dry avalanches which can run further than expected in steep terrain, especially in gullies where the sluffs can gain mass and travel far. Cold temps are the other big concern...be prepared for any delays! CJ

Weather Forecast

Continued light snow is expected for Friday night and Saturday morning with accumulations of 5-10 cm possible. Temperatures Friday night could be in the -30`C range with highs on Saturday near -20`C. After that the arctic high reestablishes itself with clear skies and continued cold temperatures through the New Year. Dress warm!!!

Snowpack Summary

The surface snow is facetting quickly with the cold temperatures. Some isolated thin, hard wind slabs observed in lee areas of the alpine. The Dec.15 layer of surface hoar (below 2100m) and hard surfaces or facets (depending on location) is down 20-30 cm. Below this is a generally supportive snow pack with multiple crusts, that is slowly weakening.

Avalanche Summary

Several observations Friday of natural or controlled loose dry avalanches up to size 1.5, running all the way to the run out zones after being initiated in steep terrain. These sluffs consist of loose surface facets and are gaining enough mass to easily push skiers and climbers around. A few very thin stubborn alpine wind slabs were also reported.

Confidence

Due to the number of field observations

Avalanche Problems

Loose Dry

The cold temperatures have facetted the surface snow, and once initiated these sluffs can pick up mass and travel far. A heads up for big sluffs if you are climbing in gullies with steep terrain above, or skiing steep lines.

The volume of sluffing could knock you over; choose your climb carefully and belay when exposed.On steep slopes, pull over periodically or cut into a new line to manage sluffing.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 2