Avalanche Forecast
Issued: Jan 7th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Persistent Slabs and Deep Persistent Slabs.
MH,
Avalanche Canada
The persistent weak layers are most likely to be triggered from shallow, rocky areas. Do your best to avoid these locations.
The snowpack is thin, the alders are tall and rocks are still hard. Regardless of these facts, good snow quality still exists in Rogers Pass.
Summary
Confidence
Moderate
Avalanche Summary
No human-triggered avalanches reported within the last few days.
MacDonald Gully 8 produced a sz 1.5 wind slab avalanche on Saturday.
On Thursday, the Macdonald gullies produced several large avalanches during a brief wind spike in the morning, notably gully #6 produced a size 3 slab avalanche.
Snowpack Summary
The top 30cm of snow is settling with warmer temps. Wind-affected snow can be found in the alpine and open areas at treeline. Steeper solar aspects have a thin sun crust that is now buried by 5-10 cm.
The December 23rd facet interface is down ~50cm and appears to be gaining strength, but remains a concern in shallow snowpack areas.
The November 17th facet/crust/surface hoar layer is down ~100cm and has become less reactive in snowpack tests, though when it does fail it is 'sudden' in character.
Weather Summary
Sunday will see mainly cloudy skies with up to 5cm of snow accumulation. Ridgetop winds will be 20-35km/hr from the South and the alpine temperature will range from -8 to -3.
5-10cm of snow is forecasted for Monday with a slight drop in temperatures and an increase in winds. Another 5-10cm on Tuesday.
Terrain and Travel Advice
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Problems
Wind Slabs
Gusty winds and warming temps have built fresh windslabs in exposed areas in the alpine. If triggered these wind slabs could step down to deeper instabilities.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Persistent Slabs
30-60cm of settled snow buries the Dec 23 facet interface. This layer will be a concern in thin rocky areas, on convex rolls, or in areas where the snowpack is unsupported.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
The Nov 17 layer, down 60-120cm, consists of facets, a rotting crust, and decomposing surface hoar. Though becoming less likely to trigger, the resulting avalanche would be quite destructive.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 8th, 2023 4:00PM
