Avalanche Forecast

Moderate - Uncertainty is due to the limited number of field observations. Uncertainty is due to the extreme variability of wind effect on the snowpack.

Wednesday Overnight: Clear skies with 10-40 km/h northeast winds. Low of -32 C.

Thursday: Increasing cloud cover in the afternoon, possible flurries late afternoon. 20-45 km/h northerly outflow winds. Temperatures rising to around -25 C.

Friday: Partially cloudy with light flurries in the morning, clearing into the afternoon. Northerly winds 40-60 km/h, easing to 20-40 km/h in the afternoon. Temperatures dropping to -30 C.

Saturday: Mainly clear, light southeast winds. Alpine temperatures around -35 C.

On Tuesday in White Pass, a natural avalanche cycle occurred as a result of northerly outflow winds forming wind slabs in an atypical, reverse-loading pattern on top of a weak layer of facets. Natural wind slab avalanche up to size 2.5 where observed from the highway corridor. 

Recently formed wind slabs may remain reactive to human triggers for longer than is typical due to the weak facets (sugary snow) they are sitting on.

On New Years Eve, the region received around 30 cm of new snow. In the past week, strong winds shifting from southwest to northeast has redistributed this new snow into wind slabs on all aspects as well as heavily wind effected the surface on all aspects and elevations.

A weak layer of facets (sugar snow) exists underneath the new snow, formed by prolonged clear skies and cold temperatures earlier in the month. Recently formed wind slabs may remain reactive to human triggers for longer than is typical due to the weak layer they are sitting on.

The lower snowpack is made up of weak sugary snow. An avalanche at this interface is most likely to be triggered in shallow areas or with a large impact like a cornice fall or a larger wind slab avalanche that steps-down to these deeply buried basal facets.

• Recent wind has varied in direction so watch for wind slabs on all aspects.
• Keep your guard up at lower elevations. Wind slab formation has been extensive.
• Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
• Be aware of the potential for large avalanches due to the presence of a deep persistent slab.
• Avoid shallow, rocky areas where the snowpack transitions from thick to thin.