Avalanche Forecast

Issued: Nov 8th, 2018 3:00PM

The alpine rating is moderate, the treeline rating is low, and the below treeline rating is below threshold. Known problems include Deep Persistent Slabs.

Alberta Parks KESAdmin, Alberta Parks

We spotted a healthy sz 2.5 on Tent Ridge during our drive today. While Tent Ridge is a known performer, it is very unusual to have an avalanche of this size so early in the season. Be very cautious on, or near slopes that have the Oct 26 crust.

Summary

Confidence

Moderate - Due to the number and quality of field observations

Weather Forecast

Temps will be steady around -10 tomorrow with some light cloud cover and flurries starting mid morning. Amounts won't add up to anything significant. Winds will be light from the west.

Avalanche Summary

The east face of Tent Ridge avalanched sometime within the last 12hours (as of 11am this morning). It was a healthy sz2.5, possibly even a sz3. The debris wasn't visible to confirm. It looked like a cornice and/or rapid warming trigger and appeared to fail on the Oct 26 crust. East aspect and wind loaded from an earlier wind event.

Snowpack Summary

The distribution of snow still varies throughout the range, but in alpine areas along the Spray Range, there is enough snow to make avalanches an issue. Highwood Pass is a bit further behind, but there are certainly areas there that also have enough snow. The alpine snowpack is made up of a few significant layers: The basal layers, the Oct 26 crust, and the surface slabs. The basal layers are already facets and some depth hoar in shallow areas. The Oct 26th crust is an unwanted "gift" from the early September snowstorm. Direct observations are limited, but it seems the crust is intact with facets above and below. This Deep Persistent layer will be the one to watch for some time. It is buried anywhere between 20cm and 80cm in blown in areas. In some areas, there is also a second crust that has been reported.

Problems

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
Deep persistent layer?? Already? Yes. This only means the trouble layer is near the bottom of the snowpack. The "deep" part is a bit of a misnomer in these parts. This layer is widespread in the alpine, but becomes more spotty at lower elevations.
Be aware of the potential for wide propagations.Carry avalanche safety equipment on ice climbs in avalanche terrain.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 3

Valid until: Nov 9th, 2018 2:00PM