15cm of snow (rain at lower elevations) is possible Wednesday with extreme winds. A further 25 to 30cm are expected Thursday. As we transition to a period of higher danger levels, conservative route choices are in order.
Confidence
Fair - Timing, track, or intensity of incoming weather is uncertain
Weather Forecast
Freezing levels will rise to 1900m on Wednesday and over 2000m on Thursday as a warm storm front moves into the region. Winds are expected to be sustained at over 100km/h for the next couple of days. Wednesday could see upwards of 15cm of new snow with a further 25 to 30cm on Thursday.
Avalanche Summary
Nothing new observed today.
Snowpack Summary
Sun crusts are present on solar aspects up to at least 2400m. Snowpack remains weak and facetted at lower elevations. At alpine and treeline elevations soft slabs and hard slabs are widespread and are found on all aspects. These slabs vary significantly in their sensitivity to triggers, with one size 2.0 slab triggered by solar radiation on a south aspect yesterday .
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.