Look up lots today and avoid slopes with cornices above them. Cornice failures are expected due to daytime warming or by people traveling along ridges. A section of cornice hurtling down slope is a real concern, it may also trigger slab avalanches.
It may take a while for temps to warm up today, but when they do loose avalanches are possible due to strong solar. This is especially likely on steep solar aspects and around cliff and rocky outcrops. Loose avalanches may trigger deeper slabs.
Isolated wind slabs in the alpine and near ridge crests have surprised a few skiers. These likely exist in steep, aggressive terrain where even a small avalanche could have severe consequences.
Deep persistent slabs are best managed by:
Cornices are best managed by:
Lots of sun, warming temperatures, and calm to light SW winds are expected today and Monday. High cloud may form this afternoon and reduce solar inputs. Solar aspects, starting with easterly in the mornings, will receive strong solar. By Monday, air temps will be closer to 0'C and the effects of the sun will be greater. Clouds will increase on Tues
Cool temps and clouds have reduced solar effects; a sun crust has formed only on steep, solar aspects. Elsewhere, 25cm of dry snow exists above 1400m. Tests on two surface hoar/crust layers in the top 1.5m indicate that they may be triggered by large loads (like cornices) in some areas (most likely on solar aspects). The snowpack below is strong.
Natural avalanches were triggered during sunny breaks yesterday. 7 size 2 to 2.5 avalanches were observed mid day from solar aspects. Many were loose, with moist debris and a few triggered slabs. Very large cornice failures were reported throughout the Selkirks yesterday. One cornice failure was reported to be 120m long and triggered a size 4!