Avalanche Forecast

Fair - Timing, track, or intensity of incoming weather system is uncertain

Friday night and Saturday: Mainly Cloudy with light snow bringing 10-20 cm (or more) of total accumulation (drainage dependant). Freezing level around 1500 m and Moderate SW alpine wind. Sunday: Unsettled conditions with snow flurries bringing another 5-10cm to some areas. Freezing level around 1500 m and Moderate SW alpine wind. Monday: A mix of sun and cloud with isolated light flurries. Freezing level around 1500 m and light wind.

Reports from Thursday suggest that natural storm and wind slab avalanche activity is tapering off, but fresh slabs and loose surface snow remain sensitive to human triggers, with avalanches up to size 2.5. Recent very large deep persistent slab avalanches in neighboring regions highlight a low probability, but high consequence avalanche problem that also plagues the South Columbia region. These highly destructive and largely unpredictable avalanches are expected to be isolated, but certainly possible anywhere at anytime.

Weaknesses within and under the 40-70 cm of rapidly settling recent storm snow are currently reactive to light triggers, especially on wind-loaded slopes. Three persistent weaknesses contribute to a highly variable, fundamentally unstable, complex snowpack with step-down potential. The mid-March sun crust/surface hoar layer down 50-80cm still has potential for human-triggering in isolated areas. The early-March crust/facet/surface hoar layer down around 80-120cm has become less susceptible to human-triggers, but still has the potential to produce large avalanches, and we continue to see fractures stepping down to this layer. The mid-February crust/facet/surface hoar layer is typically down at least 1.5m and direct triggering has become unlikely. However, large loads like cornices or smaller avalanches stepping down can still trigger this layer and produce very large avalanches.