Avalanche Forecast

Issued: Mar 12th, 2019 4:00PM

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

grant statham, Parks Canada

Banff Yoho Kootenay.

Avalanche control will occur on Wednesday on Mt. Bosworth, Stephen, Field and Dennis. No skiing or climbing in any of these areas please. Conditions are changing with the new snow, warmer temps and wind. Stay in front of the change - it happens fast.

Summary

Weather Forecast

A system crossing the area overnight on Tuesday will deposit another 5-10 cm before it ends mid-day on Wednesday. Temperatures will remain in the -10 range and winds look to be generally light.

Snowpack Summary

Strong SW winds overnight Monday have redistributed recent snow into wind slabs in open areas above treeline. This recent snow sits over weak facets, previous wind effect or sun crusts on steep solar aspects. The mid pack varies from supportive in thicker snowpack areas to weak and completely faceted in thin areas.

Avalanche Summary

No new avalanches observed or reported on Tuesday, but small natural avalanches and spindrift were observed on Monday afternoon. Some of these traveled long distances entraining facets. Several skier triggered slabs have occurred in the last couple days, and avalanche control Sunday produced slabs up to size 2.5 running to treeline.

Confidence

Due to the number of field observations

Problems

Wind Slabs

New snow and strong SW winds have built slabs in open areas above treeline. These slabs are sitting on the weak, faceted snow that was previously on the surface and as a result can run further than expected when triggered.

Use caution in lee areas. Recent wind loading has created wind slabs.Watch for surface cracking and stiffer surface layers of snow.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Loose Dry

Previous cold temperatures created weak, faceted surface snow. In steep terrain, these facets remain easily triggered and can gain enough mass to affect skiers and climbers. Narrow gullies are where this is most concerning.

Use caution above cliffs and terrain traps where small avalanches may have severe consequences.Good group management is essential to manage current conditions safely.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

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