Avalanche Forecast
Regions: Jasper.
Happy New Year from the Jasper Forecasting team. Monitor the potential for strong winds Saturday night and wind slab activity increasing the following days.
Weather Forecast
Saturday will be cloudy and isolated flurries, -18 C, and light SW winds. There may be a 100km/hr wind event Saturday night ending mid Sunday morning. Sunday will bring more flurries, maybe 7cm of snow, -17 C, and light SW winds. Monday will be similar to Sunday but slightly warmer. The slow relative warming trend will continue into Tuesday.
Snowpack Summary
Cold temps are penetrating deep into the upper snowpack, promoting faceting. Wind slab pockets are present on all aspects, tree line and above. The mid-pack is supportive with the Dec 1st interface down ~40 cm in most locations. Basal faceting continues below the Nov 5 crust potentially amplifying the deep persistent slab problem.
Avalanche Summary
Friday's Maligne patrol noted several loose dry up to size 1.5 running far on a previous hard surface. Some Wind slabs were also noted yet were dated activity. Wednesday's patrol noted a large avalanche in steep, shallow and rocky terrain off Wilcox mt. It may have been a wind slab that initiated the deeper slab weakness. View min report here.
Confidence
Wind speed and direction is uncertain on Sunday
Avalanche Problems
Wind Slabs
Variable wind direction over the past week has caused reverse loading in some areas. A 100km/hr wind event Sunday night has the potential to raise the Wind slab hazard for Sunday and Monday with potential for loading to occur further down slope.
- Variable winds have created pockets of wind slab on all aspects.
- If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 2
Loose Dry
Significant activity of this nature was noted in the Maligne range. Cold temperatures continue to cause the surface snow to loose its structure and be active particularly on steep alpine features and can run uncharacteristically far.
- Be careful of loose dry sluffing in steep, confined or exposed terrain.
Aspects: All aspects.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 1 - 2
Deep Persistent Slabs
Recent avalanche observations have shown that deep persistent slabs can be initiated by large triggers such as surface avalanches or cornice failures.
- Pay attention to overhead hazards like cornices which could trigger the deep persistent slab.
Aspects: All aspects.
Elevations: Alpine.
Likelihood: Unlikely - Possible
Expected Size: 2 - 3