Avalanche Forecast
Issued: Feb 3rd, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
MBender,
Avalanche Canada
Recent new snow in the central and southern parts of the region has woken up persistent weak layer. Adopt a conservative approach to selecting terrain in the coming days.
Summary
Confidence
Moderate - Uncertainty is due to the speed, direction, or duration of the wind and its effect on the snowpack. Uncertainty is due to how buried persistent weak layers will react with the forecast incoming weather.
Weather Forecast
WEDNESDAY Night: Mainly cloudy with flurries, accumulation 5-10 cm, moderate to strong northwest wind, treeline temperatures around -15 C.
THURSDAY: Cloudy with flurries and accumulation 3-8 cm, strong northwest wind, treeline temperatures around -10 C.
FRIDAY: Isolated flurries, moderate northwest wind, treeline temperatures around -12 C.
SATURDAY: Cloudy with flurries, moderate northwest wind, treeline temperatures around -17 C.
Avalanche Summary
There have been numerous reports of shooting cracks and whumpfs in the past two days.
In the Renshaw area there were reports of several natural size 2-2.5 persistent slab avalanches running on surface hoar buried 40 cm on Tuesday. There were also reports of few size 2 suspected persistent slab avalanches running naturally in the lower alpine on north and east aspects.
In the Kakwa area on Wednesday morning there were reports of several size 1-2.5 naturally triggered wind slab avalanches in the alpine running on east and south aspects.Â
Snowpack Summary
In the southern part of the region from the (Torpy area south) there is likely 15-30 cm of new snow that fell Monday through Tuesday.Â
Down 30-50 cm there is likely a hard melt-freeze crust up to roughly 1600 m, weak and feathery surface hoar crystals above 1600m to the lower alpine. Otherwise the new snow sits on wind packed snow in the upper alpine.
Additionally there may be a spotty weak layer of surface hoar 40 to 70 cm deep in sheltered treeline terrain in areas around Pine Pass. See this MIN post here.
There are presently no deeper concerns in the snowpack.
Terrain and Travel
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
- Be aware of the potential for large avalanches due to the presence of a persistent slab.
- Fresh snow rests on a problematic persistent slab, don't let good riding lure you into complacency.
- Choose conservative terrain and watch for clues of instability.
Problems
Wind Slabs
New snow in the south and central parts of the region combined with moderate to strong northwest winds is creating new touchy wind slabs in lee terrain features. These wind slabs may be sitting on top of weak surface hoar crystals in lower alpine and treeline areas, which would make them more easy to trigger.
Aspects: East, South East, South, South West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
A surface hoar layer buried near the end of January down 30-50 cm has recently become reactive in the south and central parts of the region. Additionally there is a another surface hoar layer down 40-70cm in the northern part of the region around Pine Pass.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Feb 4th, 2021 4:00PM
