Caution on shady aspects in the alpine and tree line elevation bands where a persistent weak layer may be reactive. See Friday's Forecaster Blog for more details: goo.gl/8Z83CvAvoid sunny slopes if the sun does come out in full force.
Summary
Confidence
Moderate - Timing or intensity of solar radiation is uncertain on Saturday
Weather Forecast
There may be some significant periods of sunny weather on Saturday into Sunday before a weak system comes through Sunday evening. Temperatures are staying cool for this time of year. SATURDAY: Cloudy with sunny periods / Light to moderate west wind / Alpine temperature -5 / Freezing level 1400m SUNDAY: A mix of sun and cloud with isolated flurries / Light to moderate west wind / Alpine temperature -7 / Freezing level decreasing to 1000m MONDAY: Mix of sun and cloud and occasional flurries / Light to moderate southwest wind / Alpine temperature -7 / Freezing level 1000m
Avalanche Summary
On Wednesday there was a size 1 avalanche that sympathetically triggered a size 3 persistent slab avalanche resulting in a fatality. This was on a northeast aspect at 2000m, 50cm deep. Additionally there were reports of natural persistent slab avalanches size 2.5-3 on southeast through northeast aspects between 1800 and 2000m. These were reported to have happened in the previous 24-48 hours. On Monday reports show explosives and skier controlled triggered storm and wind slab avalanches to size 1.5 on north and east aspects in the alpine. On Sunday there was a report of a skier-triggered cornice failure (size 2) on a northwest aspect at 2100 m, as well as skier and sledder triggered storm slabs (size 1.5) on east and north aspects in the alpine.
Snowpack Summary
We've seen only trace amounts of new snow in the past two days. Winds, however, have been moderate to strong from the south, building fresh wind slabs and further growing cornices. Last week's storm snow has been redistributed by moderate to strong southwest winds. This snow rests on the March 21st interface, a mix of moist grains at low elevations, crusts on solar aspects at all elevations and surface hoar/facets on north/east facing features at treeline and alpine elevations. Some west facing features may have surface hoar on top of a crust. The March 21st interface has been giving variably moderate to hard sudden planar results, typically down 50-60cm on 1-2mm facets.Deeper in the snowpack, 80 to 140 cm below the surface is a combination of facets, surface hoar, and/or crust known as the mid-February layer. This interface has not been active recently.The mid and lower snowpack are strong and well settled.
mgrist,
Avalanche Canada
