Avalanche Forecast

Issued: Mar 27th, 2017 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 Cornices.

Avalanche Canada Grant Statham, Avalanche Canada

The avalanche danger is slowly improving, and we cautiously move the treeline rating to MODERATE based largely on the lack of natural avalanche activity and stronger snowpack in the Little Yoho valley. Ice climbers - start early and be done early.

Summary

Weather Forecast

Snowfall expected over the next few days, with 5 cm on Tuesday, 10 cm on Wednesday and 3 cm on Thursday. Freezing levels should reach 1800m each day, with alpine temperatures ranging from -1 to -12. Winds are generally moderate but will pick up to strong through Tuesday night.

Snowpack Summary

10-15cm of soft snow sits on 100cm of dense, rounded snow comprising the upper half of the snowpack. This sits on a variety of foundations depending on location. In shallow areas (eg: Field ice climbs) the base is weak depth hoar. In deeper areas (eg: Little Yoho Valley), the base is stronger. Shears persist in the deep facets in shallow areas.

Avalanche Summary

We traveled in the Little Yoho Valley today and did not observe any fresh avalanches from the past 24-48 hours. No reports were received of any new avalanche activity in the Field, Emerald Lake or Little Yoho areas.

Confidence

Due to the number of field observations

Problems

Persistent Slabs

An icon showing Persistent Slabs

The snowpack is stabilizing after last week's cycle, and now we are left with a classic low probability, high consequence problem. Natural avalanches have mostly ceased, but triggering is still possible - especially from large loads like cornices.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 4

Cornices

An icon showing Cornices

There has been an increasing frequency of cornice failures this past week. Be wary of this as we transition into spring (cornice season). They are a hazard underfoot on ridge crests, and from overhead if you travel below one. GIve them a wide berth.

  • Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Mar 28th, 2017 4:00PM