Avalanche Forecast
Issued: Dec 28th, 2024 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
Avalanche Canada,
Avalanche Canada
Seek out sheltered snow to avoid wind slab problems but approach any avalanche terrain with caution. A problematic persistent slab structure exists in much of the region's snowpack.
Summary
Confidence
Moderate
Avalanche Summary
No avalanches have been observed in the south of the region since a report of reactive wind slabs at Shames on Wednesday.
In the north of the region, simultaneous remote-triggered size 2.5 and size 2 persistent slabs were seen Thursday, triggered from 150 m away. They fit a pattern of increasing persistent slab activity up north, where natural avalanches up to size 3 failing on the early December crust have been focused around northwest aspects in the alpine.
Snowpack Summary
Up to 60 cm of recent snow overlies previously wind affected surfaces in the alpine and at treeline. You may find moist surface snow or thin accumulations on crust below 900 m.
Below these surface layers, two distinct weak layers exist in the top meter of the snowpack. A layer of facets and/or surface hoar down 30 to 50 cm and the more prominent early December crust down 50 to 90 cm. Observations of these layers in the Terrace area are limited, but snowpack tests by the field team produced easy, sudden results in facets on the crust 60 cm deep in the Ashman area on Friday. This structure is an active problem in the north of the region.
Treeline snow depth range from 200-280 cm. The lower snowpack has no layers of concern.
Weather Summary
Saturday Night
Cloudy with flurries bringing up to 5 cm of new snow. 5 to 30 km/h southeast ridgetop wind, increasing. Freezing level to surface.
Sunday
A mix of sun and cloud. Calm to 10 km/h variable ridgetop wind. Treeline high temperature around -4 °C
Monday
A mix of sun and cloud. 5 to 15 km/h variable ridgetop wind. Treeline high temperature -5 °C.
Tuesday
Mainly cloudy with isolated flurries. 30 to 40 km east or southeast ridgetop wind, increasing. Treeline high temperature -6 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Watch for newly formed and reactive wind slabs as you transition into wind-affected terrain.
- Be aware of the potential for large avalanches due to buried weak layers.
- Avoid steep, rocky, and wind-affected areas where triggering slabs is more likely.
Problems
Wind Slabs
Recent steady snowfall and elevated winds have been forming fresh wind slabs in open, leeward terrain.
Surface avalanches may have potential to step down to weak layers in the top metre of the snowpack.
Aspects: North, North East, East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Steady snowfall has been incrementally bringing a critical load to faceted snow on the early December crust, which is already a serious problem in the north of the region. Slabs failing on this interface have been large and destructive.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 29th, 2024 4:00PM
