Avalanche Forecast Little Yoho

Date Issued: Valid Until:

Parks Canada Conrad Janzen, Parks Canada

Avalanche Forecast

Mon Mar. 11th ยท 7:01PM

Alpine

Danger Ratings Considerable

Treeline

Danger Ratings Considerable

Below Treeline

Danger Ratings Moderate

Problems

Wind Slabs Wind Slabs
Loose Dry Loose Dry

Alpine

Danger Ratings Considerable

Treeline

Danger Ratings Moderate

Below Treeline

Danger Ratings Moderate

Alpine

Danger Ratings Moderate

Treeline

Danger Ratings Moderate

Below Treeline

Danger Ratings Low
New snow and strong winds will form slabs over the previous weak facet layer resulting in a rising hazard level. We have seen a few slides run further than expected. Make conservative terrain choices until more is known about how this new snow reacts

Weather Forecast

Upper elevation winds will remain strong Monday night then slowly diminish during the day on Tuesday becoming light by Tuesday night. 5-10 cm of new snow is forecast for Monday night and into Tuesday. Alpine temperatures will hold steady Monday night near - 10'C and begin dropping on Tuesday. Valley bottoms will see high temperatures near freezing.

Snowpack Summary

Strong SW winds 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

Small natural wind slabs and loose dry avalanches were observed in the alpine Monday afternoon as the winds increased. An avalanche incident occurred on an ice climb on Mt Stephen where a relatively small natural avalanche traveled a very long distance entraining the loose facets in the path and reaching valley bottom.

Confidence

Intensity of incoming weather systems is uncertain on Tuesday

Problems

Wind Slabs

Wind Slabs

New snow and strong SW winds are building 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

Likely

Expected Size

1 - 2.5

Loose Dry

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.Be very cautious with gully features.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2