As temperatures warm and the sun appears, make travel choices that avoid steep south aspect terrain and large overhead triggers such as cornices.
Additional snow load has likely increased reactivity on previously buried surface hoar. Be cognizant of increasing hazard, especially on wind loaded features.
Both south and north winds have redistributed new and available snow into fresh wind slabs in exposed lee terrain features at higher elevations. A buried layer of surface hoar is increasing the reactivity and propagation of wind slabs.
A weak layer of large surface hoar is found down 20-50 cm. This layer has been most active in the Shames region however with additional load we may see wider spread reactivity on this layer. Use caution on sheltered and shaded slopes where surface hoar is more likely to be preserved.
When temperatures rise and the sun appears expect on steep south aspect terrain that a natural wet loose avalanche cycle will occur. Even small wet loose avalanches can push a skier in a terrain trap such as a cliff or gulley feature.
On Thursday , avalanche activity continues to subside with activity only occurring below tree line, one large (size 2.5) glide slab on known steep rock slab features and a few large (size 2) loose wet avalanches.
On Wednesday, avalanche activity had begun to subside as only a few small (size 1) loose wet avalanche were reported that had initiated from very steep south aspect terrain at treeline elevations and below.
During last weekend, two natural size 3 persistent slab avalanches were observed. Both these avalanches ran to valley bottom and are suspected to have released on a weak layer of surface hoar. Two, size 1.5 persistent slab avalanches were remotely triggered by a helicopter on the same layer.
2 cm of new snow has bonded and settled to a well settled upper snowpack. Below 1800m moist surface snow exists on all aspects, with a melt freeze crust present on south aspects that extends up to 2000 m.
At elevations treeline and below, a weak layer of surface hoar is found 20-50 cm down in sheltered terrain and continues to be reactive to skier traffic.
A second weak layer of surface hoar and/or faceted grains may be found about 60 cm deep, particularly on shaded aspects near treeline.
The lower snowpack presents as consolidated and strong.
Friday Night
Cloudy with isolated flurries, trace amounts to 5 cm of accumulation. Light northwest winds at ridgetop. Treeline temperature -7°C. Freezing level dropping to sea level.
Saturday
Clearing in the late am, no new precipitation. Light northwest winds at ridgetop. Treeline temperature -5°C. Freezing levels 500 m.
Sunday
A mix of sun and cloud, no new precipitation. Light east winds at ridgetop. Treeline temperature -5°C. Freezing levels 500 m.
Monday
A mix of sun and cloud, no new precipitation. Light southeast winds at ridgetop. Treeline temperature -5°C. Freezing levels 500 m.
More details can be found in the Mountain Weather Forecast.
