Cooler cloudy weather is approaching, but the danger will still be moderate during the heat of the day.
Weather Forecast
FRIDAY NIGHT: Partly cloudy. Light southwest wind. Alpine temperatures drop to -5 C.SATURDAY: A mix of sun and cloud with cloud increasing over the day. Light west wind. Alpine high temperatures around 0 C with freezing level to 2000 m.SUNDAY: Mainly cloudy with isolated flurries in the afternoon and 5-10 cm of snow overnight. Light southwest wind. Alpine high temperatures around -2 C with freezing level to 1800 m.MONDAY: Light flurries continue throughout the day. Light northeast wind. Alpine high temperatures around -2 C with freezing level to 1800 m.
Avalanche Summary
Minimal avalanche activity has been reported in the Purcells over the past couple days. One small naturally-triggered wind slab was observed on a northeast alpine slope on Thursday. Looking forward, expect continuing warm, sunny weather to ramp up loose wet avalanche problems with each day's warming cycle.
Snowpack Summary
Variable new snow amounts of about 5 to 25 cm from a storm earlier in the week buried a crust in most areas above 1500 m. Below this elevation it buried variably moist or crusty surfaces. Precipitation fell as rain below about 1100 m. The snowpack below about 1500 m has been disappearing rapidly under the influence of warm temperatures, strong sunshine, and rain. The chance of loose wet avalanches increases each day as these factors break down surface crusts and bring snow to its melting point.The mid snowpack is generally consolidated and strong, but exceptions may exist on north aspects above 2000 m, where a layer of faceted grains may still be preserved beneath 40 to 60 cm of hard wind-affected snow.The base of the snowpack is composed of weak faceted snow which may coexist with a melt-freeze crust. Only one very large persistent slab was reported to have failed at this layer during last week's warming event.
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.