Avalanche Forecast
Issued: Apr 16th, 2019 4:56PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
cgarritty,
Avalanche Canada
A coastal storm has been making its way inland and forming fresh wind slabs along the way - especially in western parts of the region. Use this bulletin as a starting point and evaluate the depth and reactivity of new snow as you travel.
Summary
Confidence
Weather Forecast
Tuesday night: Cloudy with continuing flurries bringing 5-10 cm of new snow. Strong southwest winds.
Wednesday: Cloudy with continuing flurries bringing a trace to 10 cm of new snow, focused to the west and easing over the day and continuing overnight. Strong southwest winds shifting west and easing over the day. Alpine high temperatures around -3 with freezing levels to 1500 metres.
Thursday: Mainly cloudy. Storm snow totals of around 10-20 cm. Strong southwest winds easing over the day. Alpine high temperatures around -4 with freezing levels to 1400 metres.
Friday: Mainly cloudy with isolated flurries and a trace of new snow. Light west winds. Alpine high temperatures around -5 with freezing levels to 1200 metres.
Avalanche Summary
Reports from Monday included an observation of our recent snow reacting easily to skier traffic on south aspects, producing loose wet avalanches to size 1.5, particularly in areas with a thinner cover of new snow.
On Sunday natural wind slabs to size 1.5 were observed on northeast facing slopes between 1400 and 1800 m. A natural cornice failure produced a size 2.5 wind slab when it impacted the underlying slope.
On Saturday loose wet sluffing from gulley walls was reported below treeline. Avalanches were also heard, but not seen running from big unskiable terrain.
If you're out we'd love it if you would submit what you're seeing to the Mountain Information Network.
Snowpack Summary
A variable 5-20 cm of new snow is expected to accumulate by Wednesday afternoon, focused to the west of the region. The new snow will bury a new melt freeze crust that has formed at treeline and below as well as on slopes that saw sun exposure after Saturday's storm. It will add to a wind-redistributed 10-30 cm of dry snow on high elevation north facing slopes.
As we enter into mid-April we're dealing with a classic warm snowpack. At and below treeline the snowpack is becoming isothermal. We're tracking the April 4th crust which is down 15 to 30 cm below the surface on high elevation north facing slopes. Surface hoar and facets have been observed on this crust and it has recently produced sudden planar results in snowpack tests.
Problems
Wind Slabs
Watch for fresh slab development, especially in terrain near ridgecrest. High elevation north facing terrain may be harboring old wind slabs and new snow is unlikely to bond well to the underlying crust on south and west facing slopes.
- Look for signs of instability like whumphing, shooting cracks, and recent avalanches.
- Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
- New snow may be hiding recent wind slabs that were easily visible before the snow fell.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Apr 17th, 2019 2:00PM
