Persistent warm temperatures are penetrating and destabilizing the upper snowpack. Natural avalanche activity is possible especially on sun exposed slopes. Avoid travel under avalanche paths especially with looming cornices overhead.
Summary
Confidence
Moderate -
Weather Forecast
Warm temperatures persist through the forecast period. WEDNESDAY: Sunny with cloudy periods and treeline temperatures near +16 degrees. Ridgetop winds moderate from the southast and freezing levels above 3000 m. THURSDAY: Mix of sun and cloud. Treeline temperatures +10 degrees with freezing levels 2300 m. Ridgetop winds light from the southwest. FRIDAY: Cloudy with isolated rain showers and some flurries at higher alpine elevations. Treeline temperatures near +4 degrees and freezing levels dropping to 2000 m. Ridgetop winds moderate from the South.
Avalanche Summary
On Monday, a widespread natural wet loose avalanche cycle occurred and was reported up to size 1.0. As the heat continues to penetrate the snowpack we suspect natural wet avalanches will continue through the forecast period.
Snowpack Summary
Snow surfaces are variable and the heat has likely eliminated any trace of cold snow except on high elevation north features. Melt-freeze conditions (more melt then freeze at lower elevations) exist on all other aspects and elevations and signs of snowballing, surface sluffing and loose wet avalanches are current.Deeper in the snowpack a layer of weak and sugary faceted grains sits on a melt-freeze crust about 50 to 120 cm deep. This layer is most prominent in the North Shore Mountains on north aspects. With little overnight re-freeze the warm temperatures will penetrate deeper and continue to destabilize the snowpack and possible imitating larger persistent slab avalanches. It’s hard to say how many hot days and warm nights it will it take to wake up the more deeply buried weak layers that we haven't thought about in a long time.
swerner,
Avalanche Canada
