Avalanche Forecast
Issued: Feb 15th, 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
Large deep persistent slab avalanches continue to be reported in the Purcells. Be extra cautious of large steep alpine slopes, especially those getting hit by the sun.
Summary
Confidence
Moderate - Uncertainty is due to the fact that deep persistent slabs are particularly difficult to forecast.
Weather Forecast
SATURDAY NIGHT: A weak front crossing the region brings up to 10 cm in the southern Purcells and 5 cm in the northern Purcells, moderate wind with strong gusts from the west, alpine temperatures drop to -10 C.
SUNDAY: Mix of sun and cloud with some isolated flurries, moderate wind from the northwest, alpine high temperatures around -6 C.
MONDAY: Mix of sun and cloud, light wind from the northwest, alpine high temperatures around -8 C.
TUESDAY: Mostly sunny, light wind from the northwest, alpine high temperatures around -8 C.
Avalanche Summary
A few natural size 2 avalanches were reported on east facing wind-loaded slopes on Saturday and a few small (size 1) slabs have been human triggered at treeline and alpine elevations over the past few days.
Large sporadic avalanches continue to be reported every few days. On Thursday, a size 2.5 deep persistent slab avalanche was observed in steep rocky alpine terrain on a southwest slope near Golden (see the MIN report). On Wednesday, a large snowmobile triggered avalanche was reported on a convex roll at treeline at Quartz Creek (see the MIN report). 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 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.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
- If you are increasing your exposure to avalanche terrain, do it gradually as you gather information.
- Minimize exposure to sun-exposed slopes when the solar radiation is strong.
Problems
Wind Slabs
Accumulations of new snow over the past week have formed some reactive slabs in steep wind affected terrain.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
Weak snow at the bottom of the snowpack continues to pose a deep persistent slab avalanche problem. Steep rocky alpine features are the most likely trigger points. Use extra caution if big alpine slopes are getting hit by the sun.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 16th, 2020 5:00PM
