Avalanche Forecast
Regions: Northwest Inland.
Shifting winds have formed wind slabs on a variety of aspects. At this time of year the sun can have a surprisingly powerful effect on the snow. Strong solar radiation can weaken cornices and initiate point releases in powdery snow especially on steep rocky south facing slopes.
Confidence
High - Confidence is due to a stable weather pattern with little change expected.
Weather Forecast
Sunday night: Clearing, light northwest wind, low of -20.
Monday: Sunny, moderate northeast wind, high of -14.
Tuesday: Increasing cloud in the afternoon, light to moderate northeast wind switching northwest, high of -12.
Wednesday: A mix of sun and cloud, moderate northwest, high of -8.
Avalanche Summary
A natural size 2 wind slab was observed on a northeast aspect in the alpine during the strong wind event on Saturday. Previous natural activity observed on Thursday was limited to size 1-1.5.Â
Several skier triggered wind slabs size 1-1.5 have been reported over the past few days, most in predictably wind loaded lees or convexities, near ridgetop, around treeline or higher.
Snowpack Summary
10-20 cm of recent snow has been extensively wind affected at upper elevations, with exposed windward features scoured down to the crust. Below 1300 m, a surface crust has formed over moist snow.
The recent snow sits over a 10-20 cm thick rain crust which effectively caps the underlying snowpack, making human triggering of avalanches on weak layers deeper in the snowpack very unlikely. Large cornice failures may still have potential to trigger these deeper layers.
Terrain and Travel
- Recent wind has varied in direction so watch for wind slabs on all aspects.
- Small avalanches can have serious consequences in extreme terrain. Carefully evaluate your line for wind slab hazard before you commit to it.
- Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.
Avalanche Problems
Wind Slabs
Wind direction has shifted from southwest during the storm through northwest, to northeast Monday. The freshest wind slabs may be found on atypical aspects and features.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 1.5
Cornices
Cornices overhead are a primary concern during sunny, warm, or windy conditions. Cornice failures are dangerous on their own, but they also have potential to trigger large persistent slab avalanches that would otherwise be difficult to trigger.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 1.5 - 2.5