Avalanche Forecast
Issued: Feb 13th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Wind Slabs.
rbuhler,
Avalanche Canada
The likelihood of triggering the late-January weak layer is decreasing but it remains reactive and capable of producing large avalanches.
Watch for new wind slab formation on Monday in exposed high elevation terrain.
Summary
Confidence
Weather Forecast
The warm air exits the region Sunday overnight. A weak storm system is expected to bring light snowfall for Monday morning before clearing in the afternoon.
Sunday night: Increasing cloud cover, moderate SW wind, freezing levels falling to around 1000 m.
Monday: Snowfall in the morning up to 10 cm, sunny breaks in the afternoon, moderate SW-NW wind, freezing levels reaching around 1400 m.
Tuesday: A mix of sun and cloud, light to moderate NW wind, freezing levels around 1400 m.
Wednesday: A mix of sun and cloud, light to moderate NW wind, freezing levels as high as 2000 m with an inversion.
Avalanche Summary
On Saturday, a natural size 2 cornice release was reported from a steep, rocky NW aspect at 2100 m in the north of the region. Some small loose wet avalanche activity was reported from steep, sun-exposed slopes.
On Friday, a natural size 2.5 slab avalanche was observed in the Coquihalla area on a NE aspect at 1900 m which was expected to have been cornice triggered. In the north of the region, explosives triggered numerous cornices up to size 2. Two of these triggered size 2 slabs on the slopes below failing down 40-60 cm. A few loose wet avalanches were observed on steep solar aspects on Thursday and Friday.
On Wednesday, a natural size 2.5 persistent slab avalanche occurred in the Duffey Lake area on a north aspect at 2200-2300 m which failed down 80 cm on the late-January interface. This is the most recent large persistent slab avalanche in the region following several which occurred the prior weekend.
Snowpack Summary
Monday's snowfall will bury a widespread surface crust and wind-affected surfaces in exposed high elevation terrain. The new melt-freeze crust is reported to exist on all aspects and elevations except for some of the highest elevation polar aspects in the north of the region which may still hold dry snow. The crust is reported to be undergoing faceting in some areas.
The late-January crust/facet/surface hoar interface is buried down 20-70 cm. This layer was most reactive between 1700 m and 2000 m in the north of the region. While this layer now appears to be dormant in many parts of the region, recent snowpack tests suggest it is still very reactive in a few places in the north of the region and still capable of producing large avalanches if triggered.
Terrain and Travel
- Be aware of the potential for large avalanches due to the presence of buried persistent weak layers.
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Wind slabs may be poorly bonded to the underlying crust.
Problems
Persistent Slabs
The late-January weak layer is down 20-70 cm and was most reactive between 1700 and 2000 m in the north of the region. It is now likely dormant in many areas, especially where there is a supportive surface crust. However, recent snowpack tests suggest it is still reactive and capable of producing large avalanches if triggered. We have now entered a low probability, high consequence scenario with this layer.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Wind Slabs
Thin new wind slabs may form on Monday. These could be more reactive than normal given the hard crust they may be sitting on.
Aspects: North, North East, East, South East, South.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 14th, 2022 4:00PM
