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.
At upper elevations, wind has pressed surfaces and redistributed snow, wind slabs may remain reactive to rider-triggering. Last week's storm snow covered a crust on southerly aspects - expect the recent, still-dry snow to be most reactive where it settles and bonds over a crust.
Strong solar radiation and rising freezing levels may weaken the surface snow creating wet loose avalanches from solar slopes.
On Friday, several wet loose avalanches occurred on solar slopes. A few storm slab avalanches were reported (likely solar-induced or where warm temperatures encouraged the snow to settle and bond), the most impressive was a natural size 2.5 slab avalanche on SW terrain around 1800 m in the Brandywine area. A few large cornice failures were also reported, most did not trigger any slabs on the slopes below, however, large cornices are still proving reactive and the size 1.5-2.5 cornice chucks and entrained debris could still be very hazardous to a rider.
On Thursday, reactive 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.
Daytime warming and solar radiation will promote moist snow surfaces, destabilizing the upper snowpack on all aspects upwards of 1800 m and higher on solar slopes. Cornices loom over ridgelines and may become weak during periods of solar radiation and warming.
At higher elevations, up to 40 cm of recent storm snow is settling and bonding an old crust on solars and faceted snow on polar aspects. Recent southwest wind pressed surfaces and formed slabs on lee slopes at exposed treeline and into 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.
Saturday night
Starry sky with increasing clouds. South wind 15-25 km/hr. Treeline low temperature -5 C. Freezing level 1300 m.
Sunday
Increasing cloud with flurries forecast to begin Monday. Southeast wind increasing to 12-25 km/hr. Treeline high temperature +2 C, freezing level spiking around 1800 m.
MondayFlurries start Monday, 5-10 mm through the day. Southeast wind increasing to 20-30 km/hr. Treeline high temperature +2 C. Freezing level 1500 m.
TuesdayTapering flurries. Light northeast wind. Treeline high temperature +1 C. Freezing level 1400 m.
More details can be found in the Mountain Weather Forecast.
