Issued: Apr 13th, 2023 4:00PM
The alpine rating is Storm Slabs and Loose Wet., the treeline rating is , and the below treeline rating is Known problems include
Recent storm slabs that formed at upper elevations remain rider triggerable, and have been propagating widely.
At lower elevations, loose wet avalanches will be easily triggered during the heat of the day. These can gain mass quickly as they run on a widespread crust.
On Thursday, there were a few solar triggered slab avalanches, up to size 2.5 in the highway corridor.
On Wednesday, multiple solar triggered storm slab and loose wet avalanches up to size 3 were observed along the hwy corridor and in the backcountry. These avalanches showed wide propagation failing at the Mar 31 layer and running far into the runout zones.
35cm of storm snow and strong, gusty SW winds recently formed a reactive storm slab, thicker in lee features. This slab is propagating and stepping down to the March 31 layer (crust on solar aspects, facet/surface hoar on polar aspects).
The mid and lower snowpack is generally strong. However, the Nov 17 basal weakness can still be found near the ground in many locations.
Calm weather prevails into the weekend.
Friday: Mix of sun & cloud. Alpine Low -8°C, High -4°C, freezing level (FZL) 1800m. Light SW ridgetop winds.
Sat: Sunny periods/convective flurries. Low -6°C, High -4°C. FZL 1900m. Light SW winds.
Sun: Cloudy with scattered flurries (5cm). Low -5 °C, High -2 °C. FZL 1900m. Light gusting strong S wind.
Terrain and Travel Advice
- Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
- Avoid terrain traps such as gullies and cliffs where the consequence of any avalanche could be serious.
Recent storm slabs have been slow to bond to the previous surfaces of suncrust, surface hoar and/or facets. These slabs remain reactive, and have shown wide propagation. Be extra cautious in terrain without previous avalanche activity.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Watch for the recent snow to become triggerable below tree line as the day warms up. Small sluffs can gain surprising mass as they travel downslope.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Valid until: Apr 14th, 2023 4:00PM