Avalanche Forecast
Issued: Feb 14th, 2020 5:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
shorton,
Avalanche Canada
A weak frontal system crossing the region on Saturday afternoon will form fresh wind slabs. Be cautious on wind loaded slopes and large steep terrain features.
Summary
Confidence
Moderate - Uncertainty is due to unpredictable avalanche behavior.
Weather Forecast
FRIDAY NIGHT: Mostly cloudy with some light flurries and trace accumulations, moderate wind with strong gusts from the west, alpine temperatures drop to -10 C.
SATURDAY: Increasing cloud with afternoon flurries bringing 5-10 cm of new snow, moderate wind with strong gusts from the west, alpine high temperatures around -6 C.
SUNDAY: 5-10 cm of snow overnight then clearing in the afternoon, light wind from the northwest, alpine high temperatures around -6 C.
MONDAY: Mix of sun and cloud, light wind from the west, alpine high temperatures around -8 C.
Avalanche Summary
A few natural size 2 avalanches were reported on east facing wind-loaded slopes on Friday. A few small (size 1) wind slabs have been human triggered at treeline and alpine elevations over the past few days.
A large avalanche was reported at Quartz Creek on Wednesday. The avalanche was triggered by a snowmobile on a convex roll at treeline. The crown of the avalanche was 150 cm thick, but it is uncertain whether the avalanche was a thick wind slab or ran on a persistent weak layer. On Monday, two deep persistent avalanches (size 2.5 and 3) were triggered with explosives in the central part of the region, both running on north aspects in the alpine. These isolated large avalanches highlight the the importance of careful snowpack and terrain evaluation in the Purcells.
Snowpack Summary
20-50 cm of low density snow has fallen over the past week and has shown some reactivity at higher elevations where it has been redistributed it into wind slabs. This snow sits above a rain crust that extends up to 1600-1900 m. Sun crusts can be found near the surface on steep south-facing slopes. The middle of the snowpack is generally settled but the base of the snowpack contains basal facets. It remains possible to trigger these deep weak layers in shallow rocky start zones or from a heavy trigger such as a cornice fall.Â
Terrain and Travel
- Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
- Conditions may have improved, but be mindful that deep instabilities are still present.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Problems
Wind Slabs
Accumulations of new snow over the past week have potentially formed reactive slabs in steep wind affected terrain.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
A layer of weak, sugary facets persists at the bottom of the snowpack at higher elevations. Steep, rocky alpine features where the snowpack transitions from thick to thin are the likely trigger points for this deep persistent slab problem.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 15th, 2020 5:00PM
