Cooler temps are tightening up the snowpack but it will still take a bit of time to settle. Another storm is forecast to cross the region on Sunday/Monday.
Confidence
Moderate - Timing of incoming weather systems is uncertain on Sunday
Weather Forecast
Saturday should be a carbon copy of friday in terms of weather. Mainly cloudy, moderate westerly winds and light flurries with only minor accumulations. On Sunday another storm is forecast to hit the region. At this time precipitation amounts are close to 25cm with strong winds and again warm temperatures. We can expect the avalanche danger to increase if the forecast holds true.
Avalanche Summary
A few recent avalanches up to sz 2.5 were observed initiating in Alpine areas on N and E aspects. These slides started as dry windslabs, then ran down into the rain soaked snow and ran to the top of their normal runouts. The majority of avalanches observed were 30-40cm thick, 60-100m wide and ran 200-300m.
Snowpack Summary
Cooler temperatures moved in overnight and we finally saw the rain begin to turn to snow. Below 2200m the snowpack was rain soaked, lost lots of mass but it now beginning to re-freeze. Above this elevation the top 5-20cm of the snowpack was moist and isothermal. So far it seems as if 2600m was a high as the rain fell and it was snow above. So, we now have what is being called the November rain crust buried down 10-15cm up to 2600m. Above this elevation the new snow and winds have combined to build new windslabs in open areas. These new windslabs will be reactive to a skiers weight so avoid steeper areas until the snowpack has some time to settle and strengthen.
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.