Avalanche Forecast

Issued: Jan 12th, 2019 4:00PM

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

stephen holeczi, Parks Canada

Little Yoho.

The Little Yoho region has seen an improving trend in thicker snowpack areas. The uncertainty lies in places where the snowpack is thin and could dig down to deeper facet layers.

Summary

Weather Forecast

Inverted temperatures will persist for the next 3 days with 3000m temperatures in the -2 to -5C range, and valley bottom temperatures in the -10 to -15C range. Winds will be mainly light from the N.

Snowpack Summary

Snowfall since Jan2 has been redistributed by southwest winds yielding extensive wind effect in the alpine. In thick snowpack areas, the Dec 10th weak layer of facets is now down 100-150cm with a stronger snowpack below. In thin snowpack areas, there is little separation between Dec 10 and the weak depth hoar/ facets sitting 40 cm above the ground.

Avalanche Summary

Some larger natural avalanches today along the divide on Fatigue Mountain and Mount Ball. These size 3 avalanches scrubbed to ground. No avalanche sightings in the Little Yoho region.

Confidence

Problems

Persistent Slabs

The Dec.10 layer of facets and some surface hoar are down 130+cm at treeline in the fatter snowpack areas more typical in this region. The sensitivity of this layer seems more concerning at lower elevations but few observations have been made so far

Convex features and steep unsupported slopes will be most prone to triggering.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 3.5

Wind Slabs

Moderate to strong SW winds have moved a significant amount of snow over the last three days. Expect widespread wind effect in the alpine and get your guard up as you enter open areas at treeline.

If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Jan 13th, 2019 4:00PM