Avalanche Forecast

Moderate - Uncertainty is due to the fact that deep persistent slabs are particularly difficult to forecast. Uncertainty is due to the limited number of field observations.

Monday night: Clear. Moderate southwest winds. Alpine low -7 C. Freezing levels dropping to valley bottom.

Tuesday: Mostly cloudy with isolated flurries bringing a trace of new snow. Moderate southwest winds. Alpine high -4 C. Freezing level around 1400 m.

Wednesday: Broken cloud with isolated flurries bringing a trace of new snow. Moderate west to southwest winds. Alpine high -3 C. Freezing level around 1400 m.

Thursday: Mix of sun and cloud with isolated flurries bringing a trace of new snow. Moderate west to southwest winds, becoming strong at ridgetop. Alpine high 0 C. Freezing level around 1800 m.

On Monday we received reports of natural and explosive triggered windslab avalanches size 1.5-2.

On Thursday a natural size 2 wind slab stepped down to the deep persistent basal facets below a rock band, details here. 

A crust can be found on solar aspects at lower elevations due to daytime warming on Monday. Recent snow has been loaded into pockets of soft windslab in alpine lees, and is settling in the mild alpine temperatures. At lower elevations it may remain unconsolidated. It sits over widespread windslab in exposed areas at all elevations.

A well consolidated mid-snowpack overlies a generally weak basal snowpack. The bottom 10-20 cm of the snowpack consists of facets and deteriorating crusts. There is potential for this deep persistent layer to reawaken in the warm alpine temperatures later in the week.

• In times of uncertainty conservative terrain choices are our best defense.
• Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
• Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
• If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.