Confidence
Fair - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
A frontal system will approach the south coast on Thursday afternoon and should result in precipitation for Thursday night and Friday morning. A second, larger system should reach the south coast early Saturday.Thursday: Increasing cloud cover, snowfall beginning in the evening, freezing levels am: 800m pm: 1500m, ridgetop wind light SWThurs. Night/Friday: Snow 10-15cm, freezing levels am: 1000m pm: 1500m, ridgetop wind 30-50 km/h SW-WSaturday: Precipitation light to moderate, freezing levels am: 1000m, pm: 1800m, ridgetop wind 30-40 km/h SW
Avalanche Summary
The weekend saw widespread natural activity. Isolated activity was reported on Monday. No new avalanches were reported on Tuesday.
Snowpack Summary
Coquihalla and south: The surface of the snowpack is reported to be moist at all elevations and most aspects on Wednesday afternoon. A widespread surface crust is expected if we get good overnight recovery. The early March melt-freeze crust is down 60-100 cm depending on elevation. Triggering is generally unlikely but remains the problem remains an isolated concern, specifically on north aspects at higher elevations. Loose wet activity is possible from steep features during the heat of the day. Duffey Lake and north: The early March melt-freeze crust is down 60-80 cm on north aspects up to 1800 m and south aspects up to 2200 m. The mid Feb weak layer is generally now found down 90-130 cm. Freezing levels were lower in this part of the region and the snowpack has generally been more reactive than the south. Old wind slabs may still exist in isolated areas of the alpine. Lower elevations have seen rain and gone through numerous melt-freeze cycles.
Problems
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.