Warm Temps, high freezing levels and strong winds have dramatically changed our snowpack. The re-set of the snowpack we were hopeful for we didnt quite get.
Confidence
Moderate - Freezing levels are uncertain on Saturday
Weather Forecast
Temperatures are forecast to cool on Saturday by mid-day and the winds are going to be dying down. The weak pineapple express is coming to an end....Mainly cloudy with isolated flurries.Precipitation: Trace.Alpine temperature: High -5 C.Ridge wind west: 10 km/h.Freezing level: 1600 metres.
Avalanche Summary
No new avalanches were observed on Friday but visibility was limited.
Snowpack Summary
Freezing levels were around 2200m on Friday and in some areas we even saw some light rain. A tiny bit of new snow fell throughout the day but long story short no where near the 15cm that as forecast (cue the sound of a sad trumpet). We did get lots of wind thoguh and as a result, most alpine terrain is wind affected. Windward slopes are scoured and lee features have a combination of windslabs and persistent slabs. These slabs are 20-40cm thick and failing on the Jan 6th facet interface which includes mainly facets and surface hoar. Any avalanche that initiates in the Alpine seems to be gouging out the facets on the lower slopes and running far.
Problems
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.
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.