As temperatures return to normal, continue to make conservative terrain choices in wind affected terrain. Wind slabs may remain reactive to human triggers for several days.
Slabs are most prevalent at alpine elevations. Be aware wind loading may be found near ridgelines or lower on the slope than usual. Watch for crossloading in unusual features like mid slope gullies.
Naturally triggered wind slabs were reported to size 2 on Friday, in wind affected alpine features. We expect reactivity to continue.
A machine remotely triggered an avalanche on a northeast facing slope at treeline on Tuesday. It's unknown what layer this avalanche failed on, likely within the recent storm snow or on the buried melt freeze crust.
Dense wind slab exists on south facing slopes at treeline and above, from strong northerly winds. Slabs may overly wind affected surfaces or surface hoar in sheltered areas. Exposed north facing slopes may be stripped back to crust or older snow surfaces.
A crust is buried 60-80 cm deep and becomes thin and variable above 1900 m. Reports suggest this is beginning to break down.
A crust from early Dec sits 80-150 cm deep. Large avalanches observed in the region on January 6th are suspected of failing on this layer. While reports suggest this layer is becoming less reactive, it is most likely triggered in shallow areas at high elevations.
Snowpack depths vary from 120-230 cm at treeline and decrease rapidly below.
Saturday Night
Clear with northerly winds increasing overnight to 70 km/h. Treeline temperatures around-15 °C.
Sunday
Sunny with strong northerly winds easing slightly in the afternoon, 20-50 km/h. Treeline temperatures reach -10 °C.
Monday
Sunny with light northerly winds 10-20 km/h. Treeline temperatures around -8 °C.
Tuesday
Sunny with southwest winds 30-40 km/h. Treeline temperatures around -5 °C.
More details can be found in the Mountain Weather Forecast.
