If storm totals surprise us and exceed 15 cm Saturday then alpine hazard will be considerable. The region has a weak and highly variable snowpack right now, it may not take much to produce natural persistent slab avalanches, especially if storm totals approach 25 cm.
Very little is known about some of the crusts in the lower snowpack at this time, but a natural persistent slab avalanche observed Thursday suggests that persistent slabs remain problematic. It's time for conservative terrain choices, as little as 15 cm of snow could induce natural persistent slab avalanches.
This is unlikely to be much of a problem Saturday, but it's important to recognize that this is a time of change. If we get surprised with 15 cm or more of snow, watch for a shallow soft slabs and small loose dry avalanches.
It’s late November and it looks like we’re entering a more winter-like pattern this weekend. The Purcells (especially the northern section) should get a nice re-fresh from the system.
FRIDAY NIGHT: Trace of snow possible, freezing level near valley bottom.
SATURDAY: Overcast, freezing level around 1000 m, moderate west/southwest wind, 1 to 10 cm of snow possible, with another 2 to 6 cm possible Saturday night.
SUNDAY: Broken cloud cover, freezing level around 1000 m, light to moderate northwest wind, 1 to 5 cm of snow possible.
MONDAY: Broken cloud cover initially with some clearing to scattered in the afternoon, freezing level around 500 m, light northwest breeze, 1 to 5 cm of snow possible.
On Thursday In the central portion of the region a natural size 2 persistent slab avalanche was observed on a north/northeast facing slope at 2300 m. This could be a portent of things to come this weekend, especially if storm snow totals exceed 20 or so centimeters.
