Regions
South Coast Inland.
A few centimeters of snow accompanied by continued southwest wind Monday night will add to recently formed wind slabs that rest on a thin crust in many terrain features. The presence of crust may enhance the slabs sensitivity to human triggering.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain on Thursday
Weather Forecast
Continued precipitation is expected through Monday night before a brief lull in the action Tuesday and Wednesday. Thursday's system has potential to be juicy, but there is a lot of discrepancy surrounding how much precipitation it will deliver. Stay tuned for details. MONDAY NIGHT: Overcast, freezing level around 900 m, moderate southwest wind, 1 to 5 cm of snow.TUESDAY: Overcast, freezing level around 1000 m lowering through the day, moderate west/southwest wind, trace of snow expected.WEDNESDAY: Overcast, freezing level at valley bottom, light scattered wind, trace of snow possible, 1 to 10 cm possible Wednesday night.THURSDAY: Overcast, freezing level may rise as high as 800 m, strong southwest wind, 10 to 20 cm of snow possible.
Avalanche Summary
Not much to report in the way of recent avalanche activity. On Sunday a small size 1 natural avalanche and a couple small skier controlled avalanches were reported from unknown aspects/elevations. These were likely small storm slabs running above the recently formed crust.
Snowpack Summary
10 to 20 cm of recent storm snow now rests on the the January 6th crust. This crust formed after temperatures cooled on Saturday, locking up the previously moist surface snow. On Sunday moderate southwest winds likely formed wind stiffened soft slabs in lee features at and above treeline. Two successive storms at the end of December produced 50 to 80 cm of snow, which has long since settled and bonded to the underlying surface. A widespread melt-freeze crust formed in mid-December may still be an issue in the northern portion of the region where it's down 50 to 100 cm below the surface, but is likely trending towards dormancy. Around the Coquihalla this interface is now thought to be part of a well bonded mid-pack. The lower snowpack is generally strong and well settled.
Problems
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.