Stronger sunshine and warmer temperatures are the concern for Saturday. New snow that sees sun for the first time is expected to shed easily, whether naturally or with light triggers. Please post your observations to the Mountain Information Network!
Recent strong winds are suspected to to have stripped snow from windward (south to west) slopes and built fresh slabs on lee (north to east) slopes. This problem is likely to increase with elevation and toward the southwest of the region.
Full sun is in the forecast for the first time after a several days of fairly steady snowfall. Expect recent snow to shed easily from steep slopes that see direct sun. This may occur naturally or with a human trigger.
Around 10 cm of new snow accumulated over the past couple of days, bringing new snow totals from this week to a variable 15-30 cm, with the deepest amounts found in the southwest of the region. The new snow buried a melt freeze crust recently formed at treeline and below as well as on slopes that saw sun exposure after Saturday's storm. It adds to a wind-redistributed 5-10 cm of dry snow (from last weekend) on high elevation north facing slopes.
All this recent snow sits over a widespread, supportive melt-freeze crust from early April. Surface hoar and facets were previously observed on this crust on high north aspects. It remains uncertain whether it became involved in any natural avalanche activity over the past few stormy days.
At lower elevations, ongoing warm weather has been promoting isothermal snowpack conditions and melting the snowpack away.
Friday night: Clear periods. Light northwest winds.
Saturday: Mainly sunny. Light south winds. Alpine high temperatures around -2 with freezing levels to 1600 metres.
Sunday: Increasingly cloudy with isolated flurries bringing a possible trace of new snow before increasing overnight. Light to moderate southwest winds. Alpine high temperatures around -2 with freezing levels to 1500 metres.
Monday: Cloudy with scattered flurries bringing 5-10 cm of new snow, including overnight accumulations. Strong south or southwest winds. Alpine high temperatures around -1 with freezing levels to 1700 metres.
A report from Wednesday in the Howson Range describes several very large (size 3) natural loose wet and wet slab releases in steep alpine terrain on a northeast aspect. This area received around 40 mm of precipitation over the week and activity here speaks to heightened avalanche danger in areas where new snow accumulations are deepest.
If you're out we'd love it if you would submit what you're seeing to the Mountain Information Network.
