Avalanche Forecast
Issued: Jan 6th, 2020 5:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
MBender,
Avalanche Canada
Uncertainty remains as to how buried weak layers have reacted under the increased load of new snow.
Summary
Confidence
Low - Uncertainty is due to the limited number of field observations.
Weather Forecast
Monday Night: Cloudy with clear periods. Light northwest wind. Alpine temperatures around -10 C.
Tuesday: Mix of sun and cloud. Light east wind. Alpine temperatures around -12 C.
Wednesday: Mix of sun and cloud. Light to moderate west wind. Alpine temperatures around -11 C.
Thursday: Isolated flurries. Light to moderate west wind. Alpine temperatures around -10 C.
Avalanche Summary
There are no reports of avalanche activity over past two days.
A widespread avalanche cycle is likely to have occurred throughout the southern part of the region on Friday and Saturday, when more than 40 cm of snow fell.
Before the storm, reports of persistent slab avalanches associated with buried surface hoar were trickling in, from Ashman, Telkwa and Howson areas. They included natural and artificially triggered avalanches ranging in size from 1.5-3, and have occurred on all aspects mainly at treeline but also in the alpine. The new snow load will increase the size and consequences of avalanches on these layers.
Snowpack Summary
40-60 cm of recent storm snow has been highly wind affected in the alpine. Expect to find deep wind loaded pockets below ridgetops and the lee sides of exposed features.
A couple of layers of surface hoar are now buried 50-100 cm below the surface in sheltered areas around treeline. Reports of avalanche activity on these layers before the last storm suggest they may be active, especially now that they are under additional snow load.
Terrain and Travel
- Closely monitor how the new snow is bonding to the old surface.
- Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
- Be aware of the potential for large avalanches due to the presence of a persistent slab.
- Uncertainty is best managed through conservative terrain choices at this time.
Problems
Storm Slabs
40-60 cm of recent storm snow and strong southwesterly winds have promoted storm slab formation in lee features with deepest amounts in lee terrain. Watch for solar triggering of recent snow on solar aspects during periods of sun.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
A couple layers of surface hoar are now buried 50-100 cm deep. There is uncertainty as to how the buried weak layers have reacted to the new load of storm snow. Human triggering of weak layers at this depth is definitely possible.
Aspects: All aspects.
Elevations: Treeline.
Likelihood
Expected Size
Valid until: Jan 7th, 2020 5:00PM
