Over the last week there have been periodic, very large, avalanche events involving the Dec 1st layer, which is a bit unsettling. This is a low probability / high consequence problem that will be lurking in the snowpack for the rest of the season.
Moderate to strong winds on Sunday were likely building fresh wind slab in the Alpine and down into tree line. These may have buried surface hoar or a preserved stellar layer and could be sensitive to human triggering.
This layer has been recently active and in some instances has been enough to step down to the deeper Dec 1 curst/facet layer. Investigate the snowpack before committing to your line.
The Dec 1 crust/facet layer woke up this past week, resulting in numerous very large avalanches This is now a low probability / high consequence avalanche problem. It will be stubborn to trigger, but if it goes the results will be very large.
The upper ridge of high pressure will break down, collapsing the temperature inversion, bringing freezing levels back down to valley bottom. Monday will see mainly cloudy skies with isolated flurries and sunny periods. Freezing level up to 1400m with an alpine high of -6 and 15-35km/hr North Westerly winds. No 'real' snow amounts in the forecast.
Up to 35cm of recent snow now buries the Jan 20th (2-4mm) surface hoar. The Jan 11 (2-5mm) surface hoar is down ~70-90cm. The Dec 1 crust/facet combo is down ~1.5 - 2.5m. Widespread wind affect at tree line and above with pockets of wind slab.
Avalanche Control on Sunday produced results up to size 3, one of which stepped down to the Dec 1st layer. Skiers were trigger small wind slabs up to size 1.5 on steep rolls.
Avalanche Control on Saturday, just West of the Park produced several size 4 - 4.5 avalanches, extending historical trim lines through mature timber.
