An avalanche cycle is slowing down slightly, but very touchy conditions remain due to extensive wind slab development. It is time to be extremely cautious in your route selection, and avoid any overhead hazard.
Weather Forecast
Wednesday looks like a mix of sun and cloud with no new snow fall and moderate westerly winds A cold morning will then warm up to around -12 °C. Thursday brings another wave of precipitation with 15 to 20cm of snow expected, but this time it will be warm and windy when the storm hits us. Flurries are expected on Friday.
Avalanche Summary
A widespread avalanche cycle up to size 2.5 has occurred on all aspects at all elevations. Many of the fracture lines and debris piles have become hidden, as a large number of these slides occurred during the big storm and were subsequently covered by further snowfalls. Numerous loose dry and wind slab avalanches also occurred today, so the cycle is not quite over yet.
Snowpack Summary
Storm snow totals in excess of 100cm have fallen at Treeline elevations in the previous 3 days. This snow has been drastically redistributed by strong winds and wind slabs now dominate Alpine and Treeline areas. In many areas this storm snow / wind slab condition sits on a previously formed very dense wind slab, which may provide an ideal sliding layer. Forecasters have a concern that the recent new load will cause failures in the deeply buried weak layers of Dec 18 and Nov 12, causing deep 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.
Loose Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.
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.