Avalanche Forecast
Issued: Jan 4th, 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.
shorton,
Avalanche Canada
Be cautious of slopes being loaded my new snow and wind where human triggered avalanches are likely.
Summary
Confidence
Weather Forecast
Frontal systems cross the region on Monday night and again on Wednesday afternoon.
MONDAY NIGHT: 5-10 cm of snow, moderate southwest wind, treeline temperatures around -4 C.
TUESDAY: Flurries easing off in the morning then some sunny breaks in the afternoon, moderate to strong west wind, treeline temperatures around -6 C.
WEDNESDAY: Scattered flurries throughout the day with up to 5 cm of snow, moderate southwest wind, temperatures around -4 C.
THURSDAY: Scattered flurries 5-10 cm of snow, light northwest wind, temperatures around-6 C.
Avalanche Summary
Over the weekend there were numerous large (size 2-3) natural storm slab avalanches at alpine and treeline elevations, and some smaller (size 1) human triggered storm slabs. Natural and human triggered slab avalanches remain a concern with more snow and wind on the way on Tuesday. Triggering large persistent slab avalanches remains possible, even though few avalanches have been reported over the past month.
Snowpack Summary
New snow and wind will form fresh slabs on Monday night. Up to 10 cm of new snow will add to the 10-30 cm from the weekend, creating the potential for reactive slabs on steep wind-loaded slopes. The upper snowpack consists of several layers of old wind slabs, while the lower snowpack consists of decomposing crusts and weak faceted snow. Some large avalanches were reported on these deeper layers on Dec 23 and 25, but for the most part they have not been reactive over the past few weeks. However, this snowpack structure is always a concern on steep rocky slopes with variable snowpack depths.
Terrain and Travel
- Avoid freshly wind loaded terrain features.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
- Be aware of the potential for large avalanches due to the presence of buried weak layers.
- Dial back your terrain choices if you are seeing more than 20 cm of new snow.
Problems
Wind Slabs
New snow and wind will form fresh slabs on Monday night. Up to 10 cm of new snow will add to the 10-30 cm from the weekend and form reactive slabs on wind loaded slopes.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Triggering large avalanches on weaknesses in the lower snowpack remains a possibility. In some areas the concern is weak snow around crusts 50 to 100 cm deep, while in others it is weak snow near the bottom of the snowpack. This problem is best managed by avoiding steep rocky slopes and approaching all avalanche terrain with caution.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 5th, 2021 4:00PM
