Solar radiation and daytime warming will be important in hazard assessment for the next few days, even on north slopes. Keep an eye out for large, mature cornices.
Summary
Confidence
Fair - Freezing levels are uncertain
Weather Forecast
Synopsis: A high pressure ridge will dominate the weather pattern for the next few days bringing warm temperatures and clear skies.Tonight: Clear with some cloudy periods, no precipitation, freezing level dropping to valley bottom. Ridge top winds light to moderate from the west.Wednesday: Sunny with cloudy periods, no precipitation in the forecast, freezing level rising to 1900m. winds from the south west, light to moderate.Thursday: Cloudy periods, possibility of flurries, freezing level around 1500m. Light to moderate ridge top winds. from the west possibly shifting north for a brief period.Friday: Cloudy with isolated flurries, trace of precipitation, freezing level around 1600m, light, locally moderate ridge top winds.
Avalanche Summary
We have reports of large natural avalanches occurring, most recently on north and north east aspects. A skier accidental size 2 around tree line yesterday indicates that even light loads may trigger a significant avalanche. Cornice failures and resulting large avalanches are being reported in the Kootenay-Boundary region and in the neighboring areas as well. Careful attention to daytime warming and aspect will be necessary to travel safely in the back country.
Snowpack Summary
Warm temperatures have promoted rapid settlement of the recent storm snow into a dense slab that sits above a variety of old surfaces. Overnight freezing will help seal up the surface from the weak layers buried below, at least until warm temperatures break down the surface crust, then all bets are off ! Rain up to 1900m has saturated the upper snowpack in some parts of the forecast area and will crust-over as the freezing level lowers at night. At elevations above the freezing level strong SW winds have have formed significant winds slabs in lee features. 3 persistent weak layers are still buried in the snowpack, A January 28th layer of surface hoar, facets and crusts, a Feb.10th layer of surface hoar, facets and crusts, and the March 2nd layer of surface hoar, facets and crusts. Of these layers, the Feb. 10th layer appears to still be problematic, with field reports still indicating easy and sudden planar shears on this layer, especially on north aspects. The most recent weak layer, March 2nd, will be on the radar for a while as we wait for it to bond.
bcorrigan,
Avalanche Canada
