Recent storm snow combined with significant warming is driving the avalanche hazard to HIGH, especially by the afternoon.
Check out the Forecaster Blog for additional details.
Springtime cornices are large and unpredictable. The sunshine and warming can pack a punch and lead to cornice failures. Give them a wide berth when travelling at ridge crest and avoid overhead exposure.
50-70 cm of recent storm snow sits above a crust at treeline and above. Warming and solar radiation will likely consolidate the new snow into a reactive slab, producing large avalanches. Avalanches may start as dry slabs in the alpine but entrain wet snow and run into below treeline elevations.
Even brief periods of sunshine combined with warm temperatures will weaken the snow surface on most aspects and elevations but especially on sun-exposed slopes, creating wet avalanches.
Thursday: Cloudy with some sunny periods in the morning. WARM. Freezing levels rise to 2500 m by the afternoon. Alpine temperatures +3C and ridgetop wind moderate to strong from the southwest.
Friday: No overnight refreeze and WARM. Cloudy with snow above 1500 m 10-15 cm. Freezing levels stationary at 2500 m with alpine temperatures near +3C. The freezing level should start to fall overnight and into Saturday.
Saturday: Cloudy with new snow up to 10 cm. Freezing levels drop to the valley bottom and ridgetop winds switch to the northwest.
No recent reports since last weekend.
Warm temperatures and will likely trigger a natural avalanche cycle on Thursday and Friday
On Sunday, a small natural wind slab avalanche was observed on a north aspect in the alpine. A rider triggered a small slab avalanche on the same slope. Both avalanches likely occurred on Saturday.
On Saturday, many natural dry loose avalanches were reported in steep terrain, as well as a large cornice failure that released a slab on the slope below.
Thursday's warming will likely create moist/ wet surface snow on all aspects and elevations besides high true North.
25 to 50 cm of new storm snow blankets upper elevations with the greater snowfall amounts being in the Renshaw. Strong west to southwest wind will be redistributing the new storm snow in exposed high elevation terrain forming touchy wind slabs and developing large cornices. The upper 60 cm of the snowpack consists of multiple crusts.
30-70 cm of snow sits on the thick melt-freeze crust from late March.
