The Public Avalanche Forecasts and Danger Ratings will come to an end on Tuesday. General spring messaging will be found under the Forecast Details tab.
Confidence
Fair - Due to limited field observations
Weather Forecast
The Interior will remain under a cool, dry North-West flow through Tuesday. A slow warming trend will persist until the end of next week.Sunday: Scattered-broken cloud cover, allowing some sunshine through. Ridgetop winds will blow light from the North. Freezing levels 900 m and falling to valley bottom overnight.Monday/Tuesday: Mostly clear, sunny skies. Ridgetop winds will blow light from the West. Freezing levels 1400 m in the afternoon and falling to 1000 m overnight.
Avalanche Summary
On Friday, numerous loose wet size 1 avalanches occurred. Additionally, a skier triggered size 1.5 slab avalanche released from an East aspect at 2250 m. The crown depth was 25 cm, width was 30 m and running 40 m in length.
Snowpack Summary
Up to 15 cm of new snow sits on melt-freeze crusts (solar aspects) and smaller surface hoar crystals on Northerly aspects. Touchy wind slabs have built on lee slopes and behind terrain features and cornices are huge and remain a concern, threatening slopes below.Buried 60-100 cm down, exists an interface of crusts and buried surface hoar. This is mainly found at upper elevations on all aspects. It seems to be slowly gaining strength, yet this interface has recently become reactive in regions further south. I would remain suspicious, especially of large, steep high-alpine slopes. Dig down, and test layer of concern.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.