Avalanche Forecast
Issued: Feb 5th, 2018 4:34PM
The alpine rating is Wind Slabs and Cornices.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Low - Intensity of incoming weather systems is uncertain
Weather Forecast
Tuesday: Cloudy with flurries (10cm snow in the south and 5 cm in the north) / Moderate west winds / Freezing level near 1100m.Wednesday: 5-20 cm of snow above 1500m in the south and up to 5-10 cm possible in the north / Moderate to strong southwest winds / Freezing level rising to 2000m in the afternoon. Thursday: 5-20 cm snow above 1000m in the south and 0-5 cm in the north / Light to moderate westerly winds / Freezing level at 1300mNote: Forecast precipitation amounts are uncertain in the south (Coquihalla) for the Wednesday-Thursday storm.
Avalanche Summary
On Saturday in the north of the region, skiers triggered a size 2 wind slab avalanche on a north east facing slope near 2050m. See the MIN report for more information.Also on Saturday in the Duffey zone, we had reports of a cornice-triggered size 3 wind slab on a north east facing slope near 2100m. See the MIN report for more information. On Wednesday in the Duffey area, explosives control triggered a size 2.5 and 2 size 3 persistent slab avalanches in north-facing alpine terrain. The early January crust was the culprit in all 3 of these avalanches. More alarming was a skier-triggered size 3 slab avalanche in the Birkenhead Lake area on the same day. The avalanche was triggered on a northwest facing slope at 2200m, was about 120cm deep and ran a distance of approximately 400m. Nobody was injured in the event. These avalanches demonstrate that you may be dealing with more than just the most recent storm snow in this part of the region.
Snowpack Summary
Recent snowfall totals are highly variable. In the south, up to 40cm of snow fell in the alpine over the past two days, while tree line elevations saw 10-20cm and temperatures near 0 degrees on Monday afternoon. In the north, new snow totals were 15-20cm in the alpine, and rapidly decreasing below 1800m.In the alpine, winds were moderate to strong from the south / east (Coquihalla) and moderate from the south / west (Duffey zone), creating fresh wind slabs in exposed down wind (lee) terrain. At lower treeline and below, warm temperatures (and rain in many locations) have created heavy snow and tough riding conditions. The new snow adds to the 80-150cm of snow that fell during the last few weeks of January. These series of storms were accompanied by strong to extreme winds which resulted in extensive scouring and impressive cornice growth in upper elevation terrain. These accumulations sit on crusts from early and mid-January which generally show signs of bonding to the overlying snow; however, they been sensitive to skier triggering in at last one recent avalanche in the north of the region (see Avalanche Activity Discussion for details).
Problems
Wind Slabs
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Cornices
Aspects: North, North East, East, South East, South.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 6th, 2018 2:00PM