Avalanche Forecast
Issued: Apr 30th, 2019 3:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Loose Wet.
jeremy.mackenzie,
Alberta Parks
A return to wintery conditions at upper elevations requires a shift in mindset. Be prepared for wind slabs in the Alpine. Otherwise, this time of year brings rapid changes to the snowpack and avalanche hazard with solar radiation and warm temps.
Summary
Confidence
-
Weather Forecast
A cool and snowy week is expected. Springtime squalls could deposit significant snow in certain areas, while other areas remain relatively dry. Winds will be mainly light, but localized strong gusts are possible.
Avalanche Summary
Avalanche observations are extremely limited at this time due to a lack of field observations.
Snowpack Summary
An upslope storm recently deposited 30 to 40cm of new snow on the eastern side of the range with only about 20cm on the western side. This snow is settling rapidly at lower elevations and becoming moist with daytime heating. Wind slabs are found in the Alpine on N and E aspects, and cool temperatures are generally keeping the snow dry in these areas. The bond of the new snow to the previous surfaces is highly variable, so take the time to evaluate this interface before committing to bigger terrain. Despite the recent snow and cool temperatures the snowpack is generally a springtime snowpack, with rapid changes caused by solar input and daytime heating. Crusts will come and go depending on the extent of the overnight freeze and the weather on any given day. Good skiing is found on upper elevation north aspects, and these can be considered more "wintery" in nature for much of the coming week with more flurries forecast and cool temperatures persisting.
Problems
Wind Slabs
Recent snow and wind have created fresh surface wind slabs in Alpine terrain. Depth of slab and bond with the underlying surface are highly variable. Dig frequently while traveling to keep a good handle on this avalanche problem.
- Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
- If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.
Aspects: North, North East, East, South East, South.
Elevations: Alpine.
Likelihood
Expected Size
Loose Wet
Loose wet slides on all aspects except north aspects in the alpine should be expected when solar input is present on daytime temperatures are warm.. These loose point releases may trigger a slab on the underlying slope.
- If triggered the loose wet sluffs may step down to deeper layers resulting in large avalanches.
- Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.
- Use extra caution on slopes if the snow is moist or wet.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Valid until: May 1st, 2019 3:00PM
