Avalanche Forecast

Moderate - Timing or intensity of solar radiation is uncertain

The ridge remains in place Friday offering one last day of seasonal normal temperatures before southwesterly flow injects a substantial amount of warm air into the South Rockies Saturday and Sunday. FRIDAY: Freezing Level climbing to around 1600 m, returning to valley bottom overnight, light northwest winds, no significant precipitation expected, mostly clear skies. SATURDAY: Freezing level starting at valley bottom then rapidly climbing to around 2800 m by lunch time, moderate west/southwest winds, no precipitation. No overnight temperature recovery expected. SUNDAY: Freezing level holding around 2800 m, moderate southwest winds at ridge top, no precipitation expected. Increasing cloud cover will likely trap warm air leading to a greenhouse situation.

On Wednesday explosive control work in the far north of the region produced numerous large to very large persistent slab avalanches on north through east facing features between 2200 m and 2400 m. Cornices were reported to be very touchy and sensitive to triggering. Over the course of the last week we have received many reports of cornice failure (some of them quite large), but no reports of subsequent slab avalanches being triggered when falling cornices impacted slopes below.

On Wednesday the field team was in the Crowsnest north area around Window Mtn, where they found 155 cm of snow on the ground at 2250 metres on a north aspect. The foot penetration was 35 cm, but the light winds were not transporting this available snow today. Ski penetration was about 15cm. In Smith Basin on Tuesday, our field team found a thinner snowpack with only 140-200 cm on the ground. They found about 10 cm of recent storm snow above a 2 cm breakable crust that was not supportive. The March 7th crust in Smith basin was down about 20 cm, with decomposing snow below that becoming facetted weak crystals deeper in the shallow weak snowpack. There were no notable test results, and evidence of aggressive slope testing on east-south-west aspects that did not trigger any releases. On Monday at 1920 metres in the Crown Mtn area there was 17 cm of new snow above a breakable 2 cm crust. Below the crust there was dry snow at this elevation. We estimate the crust extends up to about 2000 metres. Strong southwest winds have created widespread wind slabs at treeline and above.