An Arctic air mass has moved into the forecast region, bringing temperatures as low as -25°C. When recreating in the backcountry, be prepared for these cold temperatures, as even a minor setback could have serious consequences.
Strong to extreme winds with light flurries on Thursday created wind slabs 10-30 cm thick in alpine and treeline lees. During the wind event, a field team observed active natural avalanche activity on this problem, though it has since subsided.
The snowpack is generally deeper and, thus, stronger in the Little Yoho subregion than in most of the BYK forecast region. However, thin snowpack areas, such as windward and exposed terrain, will have weak basal facets at the base of the snowpack.
Minimal natural avalanche activity was observed during a flight across the forecast region on Friday. Avalanche control triggered very few slab avalanches today, with no failures on the deep persistent problem. The majority of results were loose dry avalanches, which entrained the faceted snowpack and ran far down the paths. The largest avalanche was a size 3 on Mount Field.
10 to 15 new today with strong to extreme Thursday have created winds slabs on lee features in the alpine and at treeline. The upper pack may have a thin crust under the new snow on solar aspects and a surface hoar/facet interface under last week's snow, but no avalanches observed on this layer yet. The mid-pack is generally strong; however, a weak facet layer can be found near the ground in shallow snowpack areas. At treeline, average snowpack depth ranges from 120 to 150 cm.
An Arctic air mass has moved into the forecast region, bringing cold temperatures, clear skies, and light to moderate North winds. Temperatures are expected to drop as low as -25°C over the weekend.
