Avalanche Forecast

A ridge of high pressure continues to bring sunny and dry weather with freezing levels around 3000 m even at night. On Sunday the ridge is forecast to break down bringing light precipitation and lowering freezing levels.

Friday night: Clear, light north wind, alpine low +3 C, freezing level 3000 m. 

Saturday: Sunny, light northwest wind, alpine high +9 C, freezing level 3000 m.

Sunday: Mainly cloudy with isolated flurries, 5-10 cm new snow and rain at treeline and below, moderate to strong northeast wind, alpine high +6 C, freezing level lowering to 1800 m during the day.

Monday: Mainly sunny, light north wind, alpine high +5 C, freezing level 2000 m.

Numerous wet loose avalanches to size 2 and several wet slab avalanches of size 2.5-3 and one size 3.5 were observed on steep solar aspects on Thursday. A few small wet loose avalanches in steep rocky terrain were reported on Tuesday as well as a small slab avalanche triggered by a skier on a northeast facing alpine slope. 

A couple of recent natural cornice failures size 2.5 did not trigger slabs on slopes below except for one which triggered small slab avalanches.

Neighbouring Glacier National Park reported a few very large (size 3-4) glide slab releases last week. Glide slabs are hard to predict and can release at any time, so it is important to avoid slopes with glide cracks.

The snow surface consists of a melt-freeze crust on solar aspects and shaded aspects up to treeline which transitions into moist/wet snow during the day. Dry snow might still be found on northerly aspects high in the alpine. 20-40 cm of recent snow has formed isolated pockets of wind slab on leeward slopes and behind terrain features. The recent snow sits on a series of melt-freeze crusts on all aspects below 1900 m and southerly aspects to mountain top. On North aspects in the alpine, the recent snow sits on dry wintery snow surfaces and possibly surface hoar on wind-sheltered slopes. 

Cornices are large, fragile and failing with warm temperatures. Several natural cornice falls were observed recently. 

Previous periods of warm weather are expected to have helped old persistent weak layers heal, including a few crusts buried over the last month as well as a facet layer 150 cm deep from the mid-February cold snap. However, with each day of warm weather the likelihood of persistent slab avalanches increases slightly. 

• Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.
• Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.
• Avoid sun exposed slopes, especially if snow surface is moist or wet.
• Small avalanches can have serious consequences in extreme terrain. Carefully evaluate your line for wind slab hazard before you commit to it.