Wind slab development has continued over the past 24 hours with solar warming increasing the sensitivity of this problem. Natural wind slabs have stepped down to the deep persistent layer in many locations making conservative terrain choices essential as the basal weakness starts to wake up. Expect avalanche activity to increase Friday - Sunday, particularly at lower elevations, as the temperature and solar radiation rise.
Recent storm snow accompanied by moderate southwest wind has created wind slabs in the alpine and on isolated features at tree line. Wind slabs will become more reactive on sun exposed slopes as temperatures rise. Even a small wind slab may wake up the deep persistent problem.
Loose snow avalanches will be vary from wet to dry depending on aspect and elevation. If the terrain is steep and protected from wind, a loose snow avalanche is likely. Even these smaller avalanches may trigger the deep persistent slab in isolated spots.
The bottom of the snow pack is inherently weak with well developed Facets and Depth Hoar. Wind slab avalanched have stepped down to the deep persistent slab since the last storm meaning proving that large triggers can influence this basal weakness. The likelihood is slowly increasing for this high consequence avalanche problem.
Icefields parkway- Numerous natural wind slab avalanches stepping down to the deep persistent problem up to size 3 above treeline on all but S-SW aspects. Size one dry loose/ wet loose activity observed in steep terrain at all elevations with most activity occurring on solar aspects. Natural activity notably increases as you head south from the Parkers Ridge area.
No patrol of the Maligne Lake area today.
Don't forget to post avalanche observations to the MIN.
15-20cm of recent snow has been redistributed by SW wind creating wind slabs above treeline. These fresh wind slabs sit over a sun crust on low elevation steep southerly slopes, old wind slab in expose areas, and surface facets in sheltered terrain. The mid-pack is 20 to 40cm of low density facetted snow. The lower snowpack is generally weak with large facets and depth hoar at the base. Snowpack depth varies from 60 to 170cm.
Thursday
A mix of sun and cloud.
Precipitation: Nil.
Alpine temperature: High -8 °C.
Ridge wind light to 15 km/h.
Freezing level at valley bottom.
Friday
A mix of sun and cloud.
Precipitation: Nil.
Alpine temperature: Low -11 °C, High -6 °C.
Ridge wind light to 15 km/h.
Freezing level: 1500 metres.
Saturday
Cloudy with sunny periods.
Precipitation: Nil.
Alpine temperature: Low -12 °C, High -5 °C.
Ridge wind southwest: 10 km/h.
Freezing level: 1700 metres.
Detailed weather forecasts from Avalanche Canada: https://avalanche.ca/weather/forecast
