Avalanche Forecast
Issued: Mar 8th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
jfloyer,
Avalanche Canada
Watch out on recently wind affected slopes and slopes experiencing direct sunshine. Buried weak layers in the northern part of the region may still be reactive.
Summary
Confidence
Weather Forecast
MONDAY NIGHT: Clear and cold, with alpine temperatures dipping to around -12 C.
TUESDAY: A clear start with clouds increasing through the day. Light variable winds. Alpine high temperature -3 C. Freezing level 1400 m.
WEDNESDAY: Light snow, 2-5 cm. Light to moderate southwesterly winds. Alpine high temperature -3 C. Freezing level 1400 m.
THURSDAY: Isolated flurries. Light to moderate westerly winds. Alpine High temperature -3 C. Freezing level 1200 m.
Avalanche Summary
On Sunday, only small loose dry avalanches were noted in steep terrain.
On Saturday, one size 2 wind slab on an east aspect and one size 1.5 cornice release on a northeast aspect were noted, both in the alpine.
Last week there were several notable reports of large human triggered persistent slab avalanches in the Dogtooth Range and Quartz Creek area. See these MIN reports here and here. The likelihood of triggering on these layers has since gone down, but it's still worth considering the potential for a similar release to occur.
Snowpack Summary
Dry soft snow can be found on shaded aspects above around 1500 m. On south-facing slopes and at lower elevations expect crusty snow in the morning and soft moist snow in the afternoon. Recent wind slabs and cornices still pose a hazard close to steep ridgelines.
Persistent weak layers were reactive last week, particularly in the northern end of the Purcells. The layers of concern are a buried layer of surface hoar that formed in late January is 30-60 cm deep and an older surface hoar layer is 50-100 cm deep at treeline. These layers may exist as a combination of facets and crusts at other elevations. Recent assessments indicate the chance of triggering these layers has reduced, but writing them off completely is probably premature.
Shallow rocky areas where the snowpack is thin likely have sugary facets acting as a weak layer at the base of the snowpack.
Terrain and Travel
- Be carefull around freshly wind loaded features.
- Minimize exposure to sun-exposed slopes when the solar radiation is strong.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Problems
Wind Slabs
Primarily southwest winds have created new wind slabs on north and east aspects.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Persistent Slabs
Persistent slab avalanches remain possible in the northern tip of the Purcells where there has been recent avalanche activity on a 40-80 cm deep layer of surface hoar, facets, and/or crusts (see Avalanche Summary).
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 9th, 2021 4:00PM
