Recently formed wind slabs may remain reactive to human triggering at upper elevations, particularly where they overlie a crust.
At lower elevations, a crust on or near the surface will make for challenging travel conditions, but generally safe avalanche conditions.
Recent snowfall and northwest winds may have form fresh wind slabs at upper elevations. These slabs have formed over a smooth crust and as a result, they may not bond well.
Last Friday our field team observed evidence of a natural storm slab cycle to size 2. These avalanches were generally on northwest aspects at treeline. They ran on a crust that is now 20-70 cm deep.
A crust near or on the surface may extend into the alpine from warm temperatures and rain on Monday. At higher elevations, 10-20 cm of recent snowfall has been redistributed by northwesterly winds, scouring windward slopes and depositing wind slabs in lee areas. A crust can be found down 20-70 cm that extends to mountain tops on all aspects. Recent reports suggest this crust is bonding poorly to the snow above.
The remainder of the snowpack is consolidated and strong.
Monday night
Cloudy with flurries, trace to 10 cm of accumulation. Alpine temperatures drop to a low of -3 °C. Ridge wind northwest 30 km/h gusting to 60 km/h. Freezing level 900 metres.
Tuesday
Cloudy with flurries, up to 5 cm accumulation. Alpine temperatures reach a high of -1 °C. Ridge wind 25 gusting to 55 km/h. Freezing level 1100 metres.
Wednesday
Cloudy with sunny periods and isolated flurries. Alpine temperatures reach a high of -9 °C. Ridge wind northeast 10-20 km/h. Freezing level 300 metres.
Thursday
A mix of sun and cloud. Alpine temperatures reach a high of -10 °C. Ridge wind east 5-15 km/h. Freezing level at valley bottom.
More details can be found in the Mountain Weather Forecast.
