Stay alert to changing conditions with elevation, aspect and time of day due to melt-freeze cycles. Loose wet avalanches or cornice falls may step down to trigger large persistent slabs.
As temperatures rise, large cornice falls will become a concern. They can potentially trigger persistent slabs on the slopes below. Evidence of recent cornice falls has been reported in the region.
Facets and/or surface hoar buried 40 to 80 cm deep are most prominent on north-facing slopes in the alpine. Human-trigger remains possible on thin or variable snowpack.
On Tuesday, several loose wet avalanches ran on steep south-facing slopes. On Monday, a 2.5 persistent slab avalanche was observed at Hudson Bay Mountain on a northeast alpine slope, likely triggered by a cornice fall.
Higher north-facing slopes remain suspect for triggering persistent slabs, especially with heavy loads or in areas with variable snowpack depth. Where a thick, supportive surface crust is found, triggering avalanches on buried weak layers is unlikely.
Variable wind affect and wind slab covers open terrain at upper elevations. A crust is found up to 1500 m and higher on solar slopes. New surface hoar up to 10 mm has formed on treeline and alpine features sheltered from the sun and wind.
Three layers of concern currently exist in the upper-mid snowpack. Surface hoar and a crust that formed in mid-March can be found 30 to 70 cm below the snow surface. Below this, another layer of surface hoar that formed in early March can be found at a depth of 60 to 100 cm. Additionally, a layer of facets, surface hoar, and/or a crust from mid-February is buried 120 to 200 cm deep.
The remainder of the snowpack is well consolidated, and there are no current concerns.
Wednesday Night
Mainly clear. 20 to 30 km/h northwest ridgetop wind. Treeline temperature -6 °C. Freezing level returning at valley bottom.
Thursday
Mix of sun and cloud. 10 to 25 km/h west ridgetop wind. Treeline temperature +1 °C. Freezing level 1700 m.
Friday
Mix of sun and cloud. 20 to 35 km/h southwest ridgetop wind. Treeline temperature +2 °C. Freezing level 2000 m.
Saturday
Mix of sun and cloud. 20 to 40 km/h southwest ridgetop wind. Treeline temperature +4 °C. Freezing level 2200 m.
More details can be found in the Mountain Weather Forecast.
