Watch heating on Friday especially on solar slopes. Saturday 25 mm of rain is forecast to start in the afternoon but timing is uncertain. If this arrives the avalanche danger will increase as predicted in this bulletin.
Weather Forecast
Friday will continue the spring like warm trend. Freezing level will be above mountain top with sunny periods. A big storm is forecast to arrive on Saturday midday with up to 25mm of rain to mountain top and strong SW winds. Sunday will cool down as the storm passes with freezing back down to 1800m.
Snowpack Summary
The surface snow is now moist up to 2200m with no overnight freezing. Below 1900m the whole snowpack is becoming isothermal, especially on solar slopes. Hard windslabs are in N and E start zones in the alpine and upper treeline. Shaded areas are heavily wind effected down to treeline. The snowpack is becoming quite shallow at Cameron Lake level.
Avalanche Summary
There has been continued snowballing and sluffing out of exposed rocky areas in sun exposed slopes with the warm temperatures and daytime heating. Otherwise there has been no new avalanche activity in the last couple of days.
Confidence
Intensity of incoming weather systems is uncertain on Saturday
Problems
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.
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.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.