Avalanche Forecast
Issued: Jan 9th, 2018 5:57PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs.
ghelgeson,
Avalanche Canada
Recent light density snow may be hiding wind stiffened storm slabs in wind exposed terrain at and above treeline. These slabs rest on a buried crust that may enhance the slab's sensitivity to human triggering.
Summary
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain on Thursday
Weather Forecast
The parade of Pacific storms will continue across southern B.C for the next several days, keeping alpine snow packs building through Thursday. The next system on Wednesday will be weak and affect mainly the south coast. Thursday's storm will be the main event of the week and feature moderate to heavy snow for the south coast alpine and much of the interior. The biggest snow accumulations this week will be over the South Coast and Interior Ranges.WEDNESDAY: Overcast, freezing level around 700 m, light to moderate west wind, 1 to 3 cm of snow possible. WEDNESDAY NIGHT: Freezing level around 500 m, moderate southwest wind, 5 to 15 cm of snow possible with greater accumulations in the southern portion of the region.THURSDAY: Freezing level around 600 m, moderate southwest wind, 3 to 15 cm of snow possible with greater accumulations in the southern portion of the region.FRIDAY: Overcast, freezing level around 600 m, light variable wind, no snow expected.
Avalanche Summary
Not much to report in the way of recent avalanche activity. On Monday isolated wind slabs above 2200 m were reactive to skier triggering, but were reluctant to move. 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 35 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 to strong southwest winds redistributed snow and likely formed wind stiffened soft slabs in lee features at and above treeline. A widespread melt-freeze crust formed in mid-December is still an issue in the northern portion of the region where it's down 40 to 50 cm below the surface. Recent observations have shown that there are rounding facets underneath the crust on polar aspects (north and east) at and above treeline. Recent snowpack tests have produced easy sudden-planar results on solar aspects (south and west) at and above treeline on this interface as well. 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
Storm Slabs
10 to 35 cm of recent storm snow has fallen over the last few days. The uppermost 10 to 15 cm of lighter density snow may be hiding wind slabs that were formed by significant wind out of the southwest on Sunday.
Use caution in lee areas in the alpine and treeline. A recent wind event has formed slabs.The recent snow may now be hiding windslabs that were easily visible before the snow fell.Use ridges or ribs to avoid pockets of wind loaded snow.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 10th, 2018 2:00PM
