The recent storm snow is expected to be touchy on Tuesday and human-triggered avalanches are likely.
Depending on the timing and amount of sun, solar-triggered avalanches are also possible. Extra caution is recommended around steep, sun-exposed slopes.
Cornices have grown large during the recent storm and may be fragile on Tuesday, especially with extended exposure to the sun. Falling cornices are a likely trigger for slab avalanches on the slopes below.
The recent storm snow is expected to be touchy on Tuesday, especially in wind exposed terrain.
If the sun is out for extended periods, solar-triggered storm slabs are likely.
Loose wet avalanches should be expected from steep, sun-exposed slopes during the heat of the afternoon if the sun is out for extended periods.
Unsettled conditions are expected for Tuesday as the storm system exits the region and a ridge of high pressure begins to build in its wake.
Monday Night: Snowfall 10-25 cm, strong SW wind, freezing level low around 800 m.
Tuesday: Cloudy in the morning with lingering flurries up to 5 cm, increasing sun in the afternoon, moderate to strong W wind easing through the day, freezing level high around 1300 m.
Wednesday: Mainly sunny, light to moderate SW wind, freezing level high around 1600 m.
Thursday: A mix of sun and cloud, light to moderate SW wind, freezing level high around 2500 m.
Early reports from Monday include easily triggered soft slabs below treeline in the morning and explosive-triggered soft slabs up to size 2.
On Sunday, several small skier triggered storm slabs were reported which were sliding on a melt-freeze crust as well as one isolated natural avalanche. One of these storm slabs was remotely triggered from 10 m away suggesting a weak bond between the storm snow and the underlying crust. Explosives triggered numerous small storm slabs and small cornice releases.
On Saturday, explosive triggered a few cornices including a size 2 cornice which triggered a size 1 storm slab on the slope below. Ski cutting was triggering size 1 soft slabs with 5-15 cm of recent storm snow sliding on the firm melt-freeze crust. A skier also triggered a size 1 wind slab on a north aspect at 2100 m elevation which was 15 cm thick. This MIN report describes a small skier triggered wind slab which slid on a hard crust and a small natural avalanche which was solar triggered.
As of Monday afternoon, recent storm snow totals are estimated to be 70-100 cm. This storm snow has buried a strong, supportive crust which extends to mountain top on solar aspects and to around 2200 m on northerly aspects. Strong to extreme southwest wind has redistributed the new storm snow in exposed, high elevation terrain forming touchy wind slabs and developing large cornices.
Below the crust, the upper snowpack consists of a number of crust/facet/surface hoar interfaces buried in March that seem to have bonded well during the recent warm weather.
The middle and lower snowpack are generally strong and well bonded.
