Avalanche Forecast
Issued: Feb 3rd, 2018 6:13PM
The alpine rating is Wind Slabs and Deep Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Low - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
The weather in this region will strongly depend on the position of the Arctic front that is pushing in from Alberta. Areas east of the front will have much colder temperatures and potentially heavy accumulations while areas west of the front will be warmer and receive less snow.SUNDAY: Snow increasing throughout the day with localized heavy accumulations (5-20 cm), strong west wind, alpine high temperatures around -7 C.MONDAY: Mix of sun and cloud with isolated flurries, strong northwest wind east of the divide, cold Arctic air returns with alpine high temperatures around -10 C.TUESDAY: Cloudy with scattered flurries, strong west wind, alpine high temperatures around -5 C.
Avalanche Summary
Reports are limited, but there was one explosive triggered wind slab avalanche east of the divide on Saturday. There was likely natural wind slab activity in the northeast part of the region where the heaviest accumulations occurred.On Friday, a snowmobiler was partially buried by a size 2 avalanche in the Alexander Creek drainage. The avalanche occurred on a north aspect around 2000 m and failed on weak snow near the ground. See report here. A few small wind slabs were triggered by skiers in lee terrain on Thursday and Friday.A few large persistent slab avalanches that released during last weekend's storm were observed last week as well. These avalanches failed on deep weak layers from November and December, resulting in large avalanches (size 3). Most were triggered by cornices falling on north and east facing slopes. The incoming storm has potential to trigger similar large avalanches.
Snowpack Summary
An upslope storm delivered lots of cold low density snow east of the divide on Saturday (20-30 cm). The distribution of new snow is highly variable, and so are the surface snow conditions. The western parts of the region in BC were relatively warm with less snow, while areas in Alberta and around the divide were much colder and windier which likely formed touchy wind slabs in open terrain.The lower snowpack in this region is weak, with a number of concerning weak layers. A layer buried mid-January is composed of surface hoar on sheltered aspects and a sun crust on solar aspects was and is now 30-50 cm deep. Another surface hoar layer from early-January is buried 40-60 cm deep. A widespread weak layer from mid-December composed of facets, crusts, and surface hoar is 60-80 cm deep. Finally, a rain crust with sugary facets buried in late-November is near the bottom of the snowpack. Although the snowpack structure is variable across the region, these persistent weak layers are generally widespread.
Problems
Wind Slabs
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Feb 4th, 2018 2:00PM