Regions
Northwest Inland.
It's easy to feel euphoric when the snow is deep, it's sunny, and you're out with your buds. Be careful not to let that mind set lead you out of conservative terrain Monday.
Confidence
Fair - Due to the number of field observations
Weather Forecast
Looks pretty pleasant Monday and Tuesday. The freezing level should stay at the valley bottom, there will likely be periods of sunshine and winds should be light at all elevations. The next storm system starts to affect the region Tuesday night. This one is a bit warmer, the freezing levels will likely climb throughout the storm, winds are once again expected to be strong SW at ridgetop and 1 to 5cm are expected Tuesday Night. Look for another 1 to 5cm Wednesday and an additional 5 to 10cm Wednesday night.
Avalanche Summary
On Saturday we received observations of the recent storm cycle which featured natural avalanches to size 3. The details are a bit fuzzy, but it sounds like most of this activity was limited to mid-storm instabilities. There is a good video of ski cut easily triggering a slab avalanche in seemingly benign terrain on the Bulkley Backcountry Ski Society facebook page too.
Snowpack Summary
The storm has produced approximately 30 to 70cm of dry low density snow accompanied by strong to extreme winds out of the E through SE. There are a number of weak layers in our snowpack, this storm has been a good test for all of them. Clear skies the next few days should allow operations to get out and see some terrain. Once those observations start trickling in we should have a better feel for which layers are players, and which interfaces have gone dormant/inactive. I'm curious about all the following layers: The early February surface hoar, (little is known about the distribution of this interface.) The late January crust, probably down 75 to 150cm in the south, likely shallower in the north. The mid-January rain crust (with some spatially spotty surface hoar on top), probably down 100 to 200cm. And finally, the crust/facet combination from November which is near the ground. It's not an easy snowpack to work with, we'd greatly appreciate your observations via the Mountain Information Network.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.
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.