Fresh wind slabs will overlie a weak layer of facets or surface hoar. Stick to low angled, sheltered terrain while this complex scenario plays out.
Continued snowfall and strong northwest winds will create fresh wind slabs in the alpine and treeline. Cold, clear temperatures prior to this storm have created a weak layer below the new snow, which could increase the likelihood of these avalanches occurring.
An early season crust at the base of the snowpack has shown reactivity in the southeast corner of the forecast region. This will mainly be a problem in areas with a thin, shallow snowpack. Be cautious as new snow and wind adds load to the snowpack and tests this deeper layer.
Unsettled weather continues with a series of frontal systems moving across the province. Pack your warm puffy jacket and a buff as more seasonably cold temperatures and strong winds develop!
Tuesday Overnight: 15-30cm of new snow accompanied by strong to extreme westerly winds. Winds are shifting to the northwest in the early morning, easing slightly into the strong range. Freezing levels near valley bottom with alpine temperatures around -8 C.
Wednesday: Unsettled conditions will continue as the frontal system exits northern BC. Continued strong northwest winds and another 5-10cm of snow can be expected throughout the day. Freezing levels dropping with alpine temperatures reaching -15 C.
Thursday: A weak high pressure system will develop on Wednesday night. Partially cloudy skies, isolated flurries, and moderate to strong westerly winds can be expected across the region.
Friday: A pacific storm moving over White Pass will bring snow and strong southwest winds by Friday afternoon, becoming heavier and stronger into the evening. 5-10cm of new snow accumulation can be expected through out the day.
Expect natural and rider triggered avalanches to occur as we receive significant new snow and wind. If you do head out in the backcountry, please share your observations to the Mountain Information Network!
Our North Rockies field team has started their season. They regularly post on the MIN, but you can also give them a follow on Instagram to get lots of great conditions reports and avalanche info.
Recently, a few large avalanches were observed in the Southeast corner of the region. These avalanches ran on a deep persistent layer, likely one of the crusts from late October or early November.
Another 15-30 cm of new snow overnight brings storm totals to 30-40cm. This new snow was accompanied by strong to extreme westerly winds which will build new wind slabs in the alpine and treeline.
Prior to this storm, in the south of the region, 5-10mm surface hoar growth has been observed from cold, clear nights on Sunday and Monday. Elsewhere, cold temperatures will have promoted near surface faceting. This will create a weak layer for new wind slabs to fail on, especially where a crust is present below.
The lower snowpack consists of a series of early season crusts. Cold temperatures will have promoted faceting around these crusts. Shallow alpine slopes along the eastern side of the Rockies towards Jasper may have weaker, faceted snow near the ground.
Snowpack depths at treeline range from 60cm-200cm, with the shallower value mainly in the eastern side of the range. The alpine snowpack ranges from 150cm-200cm.
