Regions
Northwest Inland.
Plan to avoid potentially wind loaded slopes just below ridge crest and areas with a thin or variable snowpack, especially if you are traveling in the alpine.
Confidence
Low - Due to the number of field observations
Weather Forecast
A frontal system is currently impacting the coast, and some spill over into the Inland region is probable. Light precipitation and strong southwest wind is expected through Saturday night. Snow and wind, albeit modest in quantity, is expected on Sunday and Monday before the ridge rebounds on Tuesday giving way to a cool dry pattern.SATURDAY NIGHT: Freezing level falling from 1400m down to around 600m through the night. 5 to 10cm of snow possible, strong to extreme southwest wind.SUNDAY: Broken cloud cover, freezing level around 500m, moderate to strong west/southwest wind, trace to 5cm of snow possible.MONDAY: Scattered cloud cover, freezing level near valley bottom, moderate to strong southwest wind, trace to 5cm of snow possible. TUESDAY: Scattered cloud cover, freezing level at valley bottom, light variable wind, no new snow expected.Visit avalanche.ca/weather for a more detailed mountain weather forecast.
Snowpack Summary
5cm of new snow fell Friday night into Saturday accompanied by moderate to strong southwest wind. This new snow rests on a wide variety of old surfaces including solar and temperature crusts on sun-exposed slopes and stiff, stubborn wind slabs in leeward alpine terrain. Feathery surface hoar and surface facets previously formed below treeline from valley bottom up to around 1500m. Approximately 30 to 50cm of snow sits on two crusts that were buried near the end of November. These crusts are widespread and extend into the alpine. Although snowpack tests have previously shown hard results at these crust interfaces, more recent observations have been limited. Below these crusts, a well settled mid-pack overlies the late October crust near the base of the snowpack. This "crust/facet combo" layer is widespread and has not been reactive to rider and remote triggers since the end of November. These rain crusts will likely be with us all winter but may not pose a problem until we see a significant change in the weather.Average snowpack depths now total 80-140 cm at treeline elevations and up to 160 cm in the alpine.
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.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.