Weather Forecast
Synopsis: A weak ridge lingering in the wake of the cold front should result in mostly dry weather Wednesday and Thursday before it breaks down Thursday night. Looks like an organized low pressure system could move into the interior Friday bringing potentially light to moderate precipitation.Tuesday Night: Freezing Level: 1700m lowering to 900m; Precipitation: 1:6mm - 1:10cm;Wednesday: Freezing Level: 900m - 1500m; Precipitation: Trace; Wind: Treeline: Moderate, W | Ridgetop: Strong, WThursday: Freezing Level: 1100m rising to 1800m; Precipitation:1:4mm - 1:5cm; Wind: Treeline: Moderate, W| Ridgetop: Strong, WFriday: Freezing Level: 1400m - 1700m; Precipitation: Trace; Wind: Treeline: Moderate, W | Ridgetop: Strong, W/NW
Avalanche Summary
No new avalanche activity to report from Monday.
Snowpack Summary
Warm temperatures resulted in the freezing level reaching to almost 2000m early this week. This has helped to settle out last weeks storm snow, it's reported to be bonding well to the old surface. Strong winds out of both the SW and NW have redistributed what little dry snow still exists at upper elevations into wind slabs immediately lee of ridge crest.Three persistent weak layers exist in the highly variable snowpack of the Cariboos:The mid-March sun crust/surface hoar layer down 50-80cm still has potential for human-triggering in isolated areas. The early-March crust/facet/surface hoar layer down around 80-120cm has become less susceptible to human triggering, but still has the capacity to produce large avalanches.The mid-February crust/facet/surface hoar combo is typically down 150 - 200cm. Direct triggering of this layer has become unlikely, however, cornice fall, a smaller avalanche in motion or prolonged warming may wake this layer up, which would result in very large and destructive avalanches.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.