Clear skies combined with the strong late-winter sun will likely initiate natural avalanche activity. Avoid being on or underneath steep sun exposed slopes. South facing features may be particularly problematic due to a buried sun crust.
Summary
Confidence
Low - Timing or intensity of solar radiation is uncertain on Saturday
Weather Forecast
We are moving into a high and dry period for the foreseeable future. Northwest flow across the province will allow a couple of shortwave troughs to ripple along the upper flow giving a mix of sun and cloud. At this time, precipitation amounts will be insignificant.SATURDAY: A few clouds, clearing mid-day, freezing level rising to around 1000 m, very light variable wind, no precipitation expected.SUNDAY: Scattered cloud cover, freezing level rising to around 600 m, light west/southwest wind, no precipitation expected.MONDAY: Scattered cloud cover in the morning, cloud building throughout the day, freezing level rising to around 600 m, light westerly wind, no precipitation expected.
Avalanche Summary
On Thursday natural avalanches to size 2.5 were reported on a variety of aspects as the snowpack adjusted to the new snow. Control work produced numerous storm slab and cornice failure avalanches to size 2 on all aspects.On Wednesday soft wind slabs up to 20 in depth were sensitive to human triggering to size 1.5. Wednesday night's storm likely initiated a cycle of natural storm slab avalanche activity.Small storm and wind slabs were sensitive to skier triggering Tuesday. Numerous skier triggered size 1 avalanches were reported from north and northeast facing features between 1450 m and 1900 m. We received a great MIN report of a large snowmobile triggered wind slab avalanche on the Brandywine Glacier that featured a 100 cm crown.
More details available here.Snowpack Summary
The Wednesday night storm produced far more snow than expected, 20 to 45 cm of slightly upside down snow fell across the region accompanied by winds out of the east, southeast and south. In wind exposed terrain the new snow rests on widespread wind damaged snow and wind slabs. In wind sheltered terrain the new snow may be sitting on a thin layer of surface hoar. The February 22nd interface is now down 50 to 70 cm, this layer is composed of old wind slabs, spotty surface hoar, facets and a sun crust on solar aspects. Snowpack testing on Thursday continues to produce planar shears at this interface. As we move into the weekend south facing slopes will be the most suspect with regard to this layer. Beneath the February 22nd interface the snowpack is well settled and strong. Variable winds in the past month have produced cornices on many ridgelines. They will become touchier as they grow in size, as temperatures rise, and when they are subject to the strong late-winter sun on clear days.
ghelgeson,
Avalanche Canada
