Avoid rocky or wind loaded features where the snowpack varies from thick to thin. This is where both wind slabs and buried weak layers can most likely be triggered.
Rider triggerable wind slabs may still be found at higher elevations on west, north, and east aspects. Avoid thin rocky features near ridgetops where wind slabs and deeper layers are most likely to be triggered.
There are three weak layers of concern in the snowpack.
First, a layer of surface hoar buried in early January. This layer has recently produced avalanches at treeline, which is where it is most prevalent.
Second, a layer of surface hoar, facets and a crust buried around Christmas. This layer has not produced avalanches in a while, but has produced some concerning test results. This layer is also most prevalent at treeline.
Third, a layer of facets and a crust found near the bottom of the snowpack. It is most concerning in the north of the region. It could potentially be triggered at upper treeline / lower alpine in shallow snowpack areas.
Two large avalanches were reported over the weekend. One, on Saturday, was potentially remotely triggered by snowmobilers at Hassler, producing a size 2 avalanche that propagated widely across a sparsely treed slope. Another, on Sunday, was a size 2 avalanche triggered by a skier in the Cariboos. This avalanche failed on a 55 cm deep surface hoar layer on a north-facing slope at 2000 m.
Several natural storm slab and wet loose avalanches occurred during the stormy weather on Friday.
Please continue to share any observations or photos on the Mountain Information Network.
Strong southwest wind and light flurries could cause some blowing snow in alpine terrain. 10 to 15 cm of recent snow is quickly settling. Fluctuating freezing level have resulted in tough travel conditions below 1800 m. Freezing levels did not get as high in the north.
A recently buried surface hoar layer is found 10 to 40 cm deep in sheltered terrain features at treeline and above. At this same depth, a crust exists on steep south facing slopes.
The two layers of greatest concern are a layer of facets, crust and surface hoar that was buried around Christmas and found around 40 to 70 cm deep. The other is a layer of large, weak facets buried in November and found near the bottom of the snowpack. This layer is likely most problematic in alpine terrain, where shallower avalanches could scrub down to these basal facets. These layers may persist for a prolonged period of time, as described in our Forecasters' blog.
In general, the snowpack is weak and shallow.
Monday night
Mostly cloudy, scattered flurries with mostly trace amounts but some isolated areas with up to 5 cm, 30 km/h southwest wind with some gusts to 50 km/h in the North Rockies, treeline temperatures around -5 °C with freezing level around 1000 m.
Tuesday
Mostly cloudy with sunny breaks in the afternoon, 40 to 50 km/h southwest wind, freezing level around 1000 m with treeline temperatures reaching -3 °C.
WednesdayCloudy with light flurries bringing 1 to 5 cm of snow, 40 to 50 km/h southwest wind, freezing level around 1000 m with treeline temperatures reaching -3 °C.
ThursdayOvernight flurries bring 1 to 5 cm of snow, mix of sun and cloudy throughout the day, 30 to 50 km/h southwest wind, freezing level drops to valley bottom with treeline temperatures around -6 °C.
More details can be found in the Mountain Weather Forecast.
