With increasing winds on Sunday we will likely see wind slab development and dry loose avalanches in the alpine. Monitor wind loading during the day and watch for an increase in avalanche hazard.
Also pay attention to the Jan 24 surface hoar layer down 30-40 cm. This layer has been reactive in this region at treeline and below.
SW winds will increase into the moderate range with strong gusts on Sunday afternoon. With all the soft surface snow around, this will start building wind slabs in lee areas of the alpine. Monitor the wind slab development Saturday night and Sunday, and use caution in or below freshly loaded areas.
A 20-40 cm slab over the Jan. 24th surface hoar layer could catch users off guard in isolated, shady aspects at treeline and below. Check the snowpack often and monitor the character and behaviour of the slab above this weak layer closely. Recent activity has been between 1600 and 1900 m.
With the lack of wind over the past several days, there is a fair bit of soft snow available for wind transport. Watch for dry loose avalanches in steep alpine terrain when the winds pick up later in the day.
No new avalanches reported in the past 48 hours, however several skier triggered avalanches have been reported in the past week.
A skier remote avalanche was reported Wednesday from Simpson area in Kootenay Park releasing on Jan 24 surface hoar at 1800m.
Last Sunday an avalanche on Jan 24 surface hoar was triggered in Little Yoho Valley in Yoho Park.
20-30 cm of recent low density snow, with minimal wind effect, overlays sun-crusts on solar aspects and scoured terrain in the alpine. The Jan 24 layer (surface hoar/crust) is down 30-40 cm at treeline and has been reactive in some areas in Yoho and Kootenay – Dig down and check for this layer before committing to steep terrain
See the avalanche section of the bulletin.
Sunday will start sunny and become a mix of sun and clouds later in the day, with clouds and light flurries expected on Sunday night. Alpine winds will be out of the SW and increase from light in the morning to moderate with strong gusts in the afternoon. Treeline temperatures are expected to be between -12°C and -6°C.
