Wind slabs may remain reactive to human triggers in isolated locations below alpine ridgetops. A persistent slab problem may still be possible to trigger in isolated areas in the north of the region and warrants continued consideration.
Lingering wind slabs may remain reactive to human triggers on steep, convex slopes below ridgetops.
Minimize exposure to cornices overhead when the sun is out.
Persistent slab avalanches may 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).
WEDNESDAY NIGHT: Few clouds / Light, northwest ridgetop wind / alpine low temperature -15 / Freezing level valley bottom.
THURSDAY: Sunny / Light, northwest ridgetop wind / alpine high temperature -4 / Freezing level 1400 m.
FRIDAY: Sunny / Light, northwest ridgetop wind / alpine high temperature -1 / Freezing level 1700 m.
SATURDAY: Sunny / Light, southwest ridgetop wind / alpine high temperature 3 / Freezing level rapidly rising to 2500 m.
On Tuesday, a size 2.5 cornice failure was reported.
There was a MIN report on Monday of a small wet loose point release triggering a size 2 slab avalanche around 30 cm. deep on a south aspect. See MIN HERE.
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.
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.
