Avalanche danger will increase during periods of strong solar radiation or rain at lower elevations.
Head out with a conservative mindset and dial back your terrain choices until the weather cools.
Westerly winds are expected to continue redistributing available snow into wind slabs in lee features in the alpine and treeline.
Cornices have grown significantly in the past two weeks. Warm temperatures may make cause cornices to become weak. Cornice failures are dangerous on their own, but also have the potential to trigger larger avalanches on the slopes below.
This is mainly a concern in the western part of the region that received greater snowfall amounts last week. 30 to 70 cm of settled storm snow has shown evidence of forming a persistent slab above weak layers. The most reactivity has been observed on south-facing aspects, with reports of a poor bond to underlying sun crust layers. Weak surface hoar crystals may also exist in isolated areas on north-facing slopes.
At lower elevations, the upper snowpack will likely stay wet and uncohosive with warm temperatures and cloud cover overnight. Wet loose avalanches will be possible out of steep terrain, especially if the sun comes out or it rains at lower elevations on Wednesday.
TUESDAY NIGHT: Mainly cloudy. Light to moderate southwesterly winds. Freezing level around 2000 m.
WEDNESDAY: Cloudy with light precipitation. Moderate to strong southwesterly winds. Freezing level around 2000 m.
THURSDAY: Partially cloudy. Light variable winds. Freezing level around 1500 m.
FRIDAY: Partially cloudy with light precipitation. Light southwest winds. Freezing level around 1600 m.
Several natural and one human-triggered wind slabs occurred on Sunday and Monday in the alpine and treeline (size 1-2).
Several notable human-triggered slab avalanches occurred last week, suggesting that the recent snow is bonding poorly to the underlying layers. These occurred on a range of aspects above 2000 m, with the most notable reactivity observed on south-facing aspects. Most slabs were small in the top 20 to 30 cm of snow (size 1), but one larger 70 cm thick slab was remotely triggered from below by a group of skiers (size 2). This avalanche occurred on a south aspect at 2250 m. (read more in this blog).
30-70 cm of settling storm snow exists at higher elevations. Snow depths taper significantly with elevation, with moist and crusty surfaces below 1800 m and on south aspects into the alpine.
In some areas, last week's snow is well bonded to old crust layers, while in other areas the snow has settled into a reactive slab above weak layers around the crusts. At this point, it appears persistent slab problems may exist in the deeper snowpack areas along the western side of the range. The lower snowpack is generally well bonded.
