Avalanche Forecast
Regions: Banff Yoho Kootenay.
15 to 30+ cm of new snow with increasing wind has bumped the hazard up over the last 24 hrs. This was more snow than expected, so depending on what happens with the weather overnight we could see a period of HIGH hazard in the alpine on Sunday.
Weather Forecast
The precipitation should slow Friday night as a ridge starts to build into the area. Temperatures will fall into the -15 to -25 C range at treeline on Saturday with some flurries expected during the day. Alpine winds will increase into the moderate to strong range and stay that way through the day.
Snowpack Summary
15-30+ cm new snow with winds increasing to strong out of the S-SW on Friday. Wind slabs building at treeline and in alpine areas as that loose snow gets blown around. These slabs may bond poorly to the underlying facets from the cold snap. The Dec 2 crust/facet interface is down 60-100 cm, and the snowpack is very faceted in shallower areas.
Avalanche Summary
Size 1-2 loose dry and wind slab avalanches were reported by local ski areas on Friday. These were triggered by ski cutting and explosive work. A few loose dry natural observations and a natural avalanche on Pilsner, Mt Dennis that dusted the Field back road was also reported. We expect more avalanche activity occurred but visibility was limited.
Confidence
Intensity of incoming weather systems is uncertain on Saturday
Avalanche Problems
Storm Slabs
15-30+ cm of new snow with increasing winds are building touchy wind and storm slabs, especially in leeward loaded areas. These could be easy to trigger with the cold facets underneath. Stick to ridges and moderate angled slopes until things bond.
- Watch for surface cracking and stiffer surface layers of snow. Avoid wind loaded terrain.
- Storm snow is forming reactive slabs.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Likely
Expected Size: 1 - 2.5
Loose Dry
The new snow will be sluffing far and fast in steep terrain due to the faceted snowpack underneath the recent snow. This could result in larger loose dry avalanches in steep terrain, gullies and chutes.
- On steep slopes, pull over periodically or cut into a new line to manage sluffing.
- Good group management is essential to manage current conditions safely.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Likely - Very Likely
Expected Size: 1 - 1.5
Persistent Slabs
The Dec. 2 crust/facets are down 60-100 cm throughout the region, but we have seen limited avalanche activity on this layer. It has mainly been a problem in Kootenay, but there is a high degree of uncertainty around this layer as we get more loading.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood: Possible
Expected Size: 1 - 2.5