Avalanche Forecast
Issued: Feb 3rd, 2017 3:34PM
The alpine rating is Wind Slabs and Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Moderate -
Weather Forecast
Saturday: Mainly cloudy with isolated flurries and a trace of new snow. Winds light from the northeast. Alpine temperatures around -20.Sunday: A mix of sun and cloud with isolated flurries and a trace of new snow. Winds light from the northeast. Alpine temperatures around -20.Monday: A mix of sun and cloud with isolated flurries and a trace of new snow. Winds light from the northeast. Alpine temperatures around -20.
Avalanche Summary
Reports from Thursday include details of a remote triggered size 2.5 avalanche that occurred in the south of the region. The slide took place on a roughly 30 degree south-facing slope at 2100 m in elevation. The remote trigger, a depth of 80 cm, and a failure plane attributed to our January 15 surface hoar all reinforce enduring concerns for persistent slab problems in the region.On Monday, several natural wind slab and storm slab avalanches up to size 2.5 were reported. These slabs were typically 30-50 cm thick and failed on a variety of aspects at treeline and in the alpine. Fresh wind slabs have since been (and are expected to remain) sensitive to light triggers, especially on steep and unsupported (convex) slopes.Persistent slab avalanches remain a serious concern for the region. Last week people triggered numerous large avalanches, several of which resulted in multiple burials. These avalanches all released on, or stepped down to, the mid-December persistent weakness down 1-1.5 m in the snowpack. Check out this list of recent near misses which includes many in the Cariboo region.
Snowpack Summary
10-60 cm of recent snow (with the largest amounts in northern parts of the region) and strong shifting winds have resulted in fresh wind slabs on a variety of aspects in wind exposed terrain. Meanwhile, cold temperatures have promoted both the faceting of surface snow as well as the growth of surface hoar on sheltered open slopes. The persistent weakness buried mid-January is now down 50-100 cm and consists of buried surface hoar in sheltered areas, and/or widespread faceted old snow. It has generally stabilized but may remain sensitive to human triggers in isolated areas, especially where buried surface hoar is preserved. Another surface hoar/facet weakness was buried mid-December and can now be found down 70 cm in shallow snowpack areas, or as much as 1.5 m in deeper snowpack areas. It woke up during the last storm and has remained reactive to human triggers. This weak layer is responsible for several large human-triggered avalanches, including some with multiple burials, and the layer may remain reactive for the foreseeable future. Click here for a new blog post with more details.
Problems
Wind Slabs
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Feb 4th, 2017 2:00PM