South Rockies

We're in a period of uncertainty as cooling temperatures gradually stabilize the snowpack. Continue avoiding large avalanche paths and overhead hazards.

Moderate -

Monday: Cloudy with sunny periods earlier in the day. Light southeast winds. Freezing level to 1500 metres with alpine temperatures around -8. Tuesday: Cloudy with scattered flurries bringing approximately 5 cm of new snow, mainly in the evening. Light south winds. Freezing level to 2100 metres with alpine temperatures around 0. Wednesday: Mainly cloudy with isolated flurries and a trace of new snow. Strong southwest winds. Freezing level to 2100 metres and alpine temperatures around 0.

Reports from Saturday included two explosives triggered Size 2 wind slabs south of Crowsnest Pass. These occurred on northeast to southeast aspects in alpine terrain and featured crown fracture depths of 20-80 cm.A report from Friday in the Crowsnest area showed a natural Size 3.5 deep persistent slab that began as a ridgetop wind slab release before stepping down to ground as it descended its track. Another explosives triggered Size 3.5 deep persistent slab was reported north of Sparwood. The resulting debris pile appeared to be roughly 10 metres high.Looking forward, recently formed wind slabs at alpine elevations will likely remain reactive to natural and human triggering on Monday, especially while the sun is out. Although cooling temperatures should reduce the likelihood of persistent slab activity over Monday, the recent scale and extent of this activity demands that backcountry users take caution with that assumption.

Light new snow accumulations over Thursday and Friday were redistributed into touchy wind slabs in alpine terrain while rain soaked the snowpack at treeline and below. Lower temperatures have since formed a crust at the rain soaked surface, which will tend to break down with daytime warming at lower elevations and on solar aspects. Below the new snow and crust, regular snowfall throughout early March saw roughly 50-90 cm of snow accumulate above the crust and facet interfaces from February. In some areas this storm snow may have a poor bond to these interfaces. Aside from that uncertainty, the mid-pack in the region is generally strong. With that said, the bottom third of the snowpack is composed of weak sugary facets roughly 1-1.5 metres deep. The potential for full-depth avalanches over this basal weakness remains a real concern, with potential triggers including wind slab or cornice releases that may initiate naturally with intense solar radiation.