New snow and strong winds overnight will increase the avalanche danger. New snow may release as loose wet avalanches when temperatures rise during the day.
Summary
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain on Thursday
Weather Forecast
10-20 cm of new snow overnight with higher amounts possible in western upslope areas. Freezing levels staying above 1300 metres with moderate to strong southwest winds. Another 5-10 cm of snow during the day on Thursday as freezing levels rise up to 1500 metres with moderate westerly winds. Some convective flurries on Friday morning with a freeze down to at least 1000 metres. Becoming mostly sunny during the day on Friday with light northwest winds and freezing levels climbing up to 1700 metres. Freezing down to 1000 metres by Saturday morning, with a mix of sun and cloud during the day.
Avalanche Summary
No new reports of persistent slab avalanches on Monday or Tuesday. Loose wet solar induced activity in most areas up to size to size 2.0, as well as some thin wind slabs in the high alpine on shaded aspects. On Sunday we had reports of natural cornice falls up to size 3.0 that triggered persistent slab avalanches on the slopes below, and solar triggered persistent slab avalanches up to size 2.5 in the alpine from slopes steeper than 40 degrees. On Saturday cornice fall produced avalanches to size 3 on north and northeast facing features between 2000 and 2400 m, failing on the late February persistent weak layer. Small natural storm and wind slabs were also reported on northwest, northeast and east facing slopes between 2100 and 2400 m.
Snowpack Summary
Forecast new snow and wind is expected to develop new storm slabs above a mix of surfaces, including crusts on solar aspects, moist snow up to treeline, and dry snow or recent wind slabs in the alpine on shaded aspects. Cornices continue to be described as large and fragile. The late February persistent weak layer is an aspect dependant mix of surface hoar, facets and/or a thick crust down around 60 to 110 cm below the snow surface. Commercial operators continue to see hard sudden planar results in snowpack tests, which suggests that wide fracture propagations are possible. New storm loading above the buried persistent weak layer may increase the likelihood of triggering large avalanches.
triley,
Avalanche Canada
