Avalanche Forecast
Issued: Jan 18th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
mconlan,
Avalanche Canada
New slabs may be touchy and the warming trend has the potential of waking up the buried weak layer. Travel conservatively during this period of uncertainty.
Summary
Confidence
Moderate - Uncertainty is due to how buried persistent weak layers will react with the forecast incoming weather.
Weather Forecast
SATURDAY NIGHT: Cloudy with snowfall, accumulation 5 to 10 cm in the south of the region and 1 to 5 cm in the north of the region, moderate to strong southwest wind, alpine temperature -8 C, freezing level below valley bottom.
SUNDAY: Cloudy with snowfall in the south of the region, accumulation 5 to 15 cm, moderate to strong southwest wind, alpine temperature -4 C, freezing level rising to 800 m.
MONDAY: Cloudy with snowfall, accumulation 5 to 10 cm, moderate to strong southwest wind, alpine temperature -2 C, freezing level 1200 m.
TUESDAY: Increasing clouds with afternoon snowfall, accumulation 2 to 5 cm, light southeast wind, alpine temperature -6 C, freezing level below valley bottom.
Avalanche Summary
Avalanche activity has quieted down over the past few days, but new snowfall in the southern half of the region and strong southwest wind will likely produce new slabs, with the most reactive being in exposed terrain at and above treeline.
Last weekend there were notable signs of a reactive persistent slab problem, including large whumpfs and a large snowmobile triggered avalanche in the neighbouring Clemina area (see the MIN report). The surface hoar layer responsible for this problem has been harder to find since then, but could still potentially produce large avalanches in certain sheltered slopes around treeline. The likelihood of triggering this layer could increase as the air temperature rises on Sunday and Monday.
Snowpack Summary
In the south of the region, around 10 to 20 cm of new snow is forecast, which will form fresh storm slabs. Across the entire region, strong southwest wind is forecast, meaning that wind slabs are likely present on exposed slopes at and above treeline.
The main concern over the past couple of weeks has been a layer of surface hoar buried 60-120 cm beneath the surface. Although an avalanche has not been reported on this layer in the past five days, the likelihood of triggering it may increase as the air temperature warms.
Terrain and Travel
- Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
- Extra caution for areas experiencing rapidly warming temperatures for the first time.
- Approach steep open slopes at and below treeline cautiously, buried surface hoar may exist.
Problems
Storm Slabs
In the southern half of the region, around 10 to 20 cm of snowfall along with strong southwest wind and a warming trend will all work together to form new slabs. In the north of the region, the howling southwest wind may produce fresh wind slabs in exposed terrain features, particularly near ridges.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
A layer of surface hoar is buried 60 to 120 cm deep. As the air temperature rises, the likelihood of triggering this layer may increase. Use added caution in clearings around treeline during periods of warming.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Valid until: Jan 19th, 2020 5:00PM
