Avalanche Forecast
Issued: Jan 18th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
zryan,
Avalanche Canada
Updated on Thursday at 7:15 AM: Wind has arrived at White Pass and created dangerous avalanche conditions on wind-loaded slopes.
Summary
Confidence
Moderate
Avalanche Summary
On Wednesday our field team observed small (size 1) natural wind slab avalanches occurring when southerly winds picked up. We expect newly formed wind slabs to be reactive to human triggering.
Snowpack Summary
25 cm of loose faceted snow exists on the surface. This overlies a firmer midpack. A decomposing crust can be found down 50-100 cm. Below this, the lower snowpack is weak and faceted.
Snow depth at White Pass is around 100 cm in sheltered areas and up to 200 cm on wind-loaded slopes. Shallower snowpack areas (< 1 m) are reported to be quite facetted and loose.
Weather Summary
Wednesday night
Mainly cloudy with snowfall, up to 5 cm of accumulation. Southerly winds increasing, gusting 20 to 40 km/h. Alpine temperatures around -10 C. Freezing level at valley bottom.
Thursday
Periods of snow, up to 5 cm of accumulation. Southerly winds 20 gusting to 45 km/h. Alpine temperatures around -10 C. Freezing level at valley bottom.
Friday
Cloudy with snowfall. Southerly winds increasing 30 to 50 km/h. Freezing level rising to 500 m. Alpine temperatures around -5 C.
Saturday
Cloudy with snowfall. Southerly winds easing 20 to 40 km/h. Freezing level near valley bottom. Alpine temperatures around -8 C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Pay attention to the wind, once it starts to blow fresh sensitive wind slabs are likely to form.
- Wind slabs are most reactive during their formation.
- Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
Problems
Wind Slabs
With the arrival of wind on Wednesday we have seen rapid wind slab formation in lee areas. Assess for changing conditions throughout the day and as you gain elevation or change aspects. Use extra caution in leeward terrain features.
Aspects: North, North East, East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 19th, 2023 4:00PM
