The March sun packs a punch and can quickly destabilize the snowpack. Be suspect of sunny slopes or overhead hazards like cornices during the heat of the day.
Recent southwest winds have formed wind slabs on lee slopes at treeline and above and may remain reactive to human triggering. In wind-sheltered terrain, the recent storm snow may have a poor bond to the underlying crust.
Large looming cornices exist along ridgelines. Cornices become weak with daytime warming and sun exposure. Give cornices a wide berth while traveling ridgelines and avoid slopes below them.
Strong solar radiation and rising freezing levels may weaken the surface snow creating wet loose avalanches from steep solar slopes.
On Thursday, relative wind slabs were reported around Whistler-Blackcomb including a size 1.5 in the Poop Chutes and a size 1.5 in S Turn (Wayne Flann Blog).
On Wednesday, skiers triggered a size 1 storm slab on a convex rollover with a crown 10-30 cm deep near Rainbow Mountain. Additionally, a few natural wind slabs were reported up to size 1 and explosive control produced several cornice falls up to size 2.5 and wind slabs to size 1.
In the northernmost end of the forecast region (near the Homathko Icefield), skiers found a reactive layer of surface hoar buried 65 cm deep below the recent storm snow, and observed natural avalanches to size 3.
On Tuesday, a few human-triggered storm and wind slab avalanches were reported up to size 2. Natural cornice failures and dry loose avalanches were also seen to size 1.
Natural and human triggered avalanche activity is possible throughout the weekend with rising freezing levels and solar radiation.
Surface snow will likely become moist to ridgetop on solar aspects by the afternoon. Cornices loom over ridgelines and may become weak during periods of solar radiation and warming.
Up to 40 cm of recent storm snow seems to be settling and bonding to the old buried snow surfaces which consist of crusts on solars and faceted snow on polar aspects. However, at upper elevations shady, sheltered aspects may still host fairly unconsolidated loose snow. Recent southwest wind formed reactive wind slabs on lee slopes at treeline and in the alpine.
Deeper in the mid-pack a couple of crusts with facets sitting above them can be found at treeline and above down 90 to 200 cm.
The remainder of the mid and lower snowpack is well-settled and strong.
Friday night
Scattered clouds and starry breaks. Treeline low temperatures -6. Southeast wind 10-20 km/hr. Freezing level 1000 m.
Saturday
Mix of sun and cloud. South wind 10-25 km/hr. Treeline high temperature +4. Freezing level 1700 m.
SundayFlurries start late in the afternoon. Southeast wind increasing to 20-30 km/hr. Treeline high temperature +2. Freezing level 1600 m.
MondayFlurries, up to 10 cm. South wind gusting to 30 km/hr. Treeline high temperature 0. Freezing level 1000 m.
More details can be found in the Mountain Weather Forecast.
