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 Storm Slabs.
cgarritty,
Avalanche Canada
An ongoing storm is ramping up avalanche danger in the region - especially in areas nearest to the coast. Treat the danger as HIGH if you encounter 30 cm or more new snow.
Summary
Confidence
Moderate - Forecast snowfall amounts are uncertain
Weather Forecast
Tuesday night: Cloudy with continuing flurries bringing 5-10 cm of new snow. Moderate to strong southwest winds.
Wednesday: Cloudy with easing flurries bringing a trace to 5 cm of new snow and new snow totals to 20-40 cm. Flurries beginning again in the evening. Moderate southwest winds increasing to strong or extreme from the south in the evening. Alpine high temperatures around -3 with freezing levels around 1200 metres.
Thursday: Cloudy with scattered flurries bringing about 10cm of new snow, including accumulations from Wednesday night. Light flurries continuing overnight. Strong to extreme southwest winds easing over the day. Alpine high temperatures around -4 with freezing levels to 1100 metres.
Friday: Cloudy with isolated flurries and a trace of new snow. Light to moderate southwest or west winds. Alpine high temperatures around -5 with freezing levels to 1000 metres.
Avalanche Summary
Ne new avalanche activity to report from Saturday or Sunday.
We received a great MIN report on Friday. It details a few avalanche occurrences including a size 3 on an east facing slope and lots of loose wet activity from steep terrain.
Snowpack Summary
About 20-40 cm of new snow is expected to accumulate on the surface at higher elevations by Wednesday morning. The new snow will bury a wind-redistributed 5 to 20 cm of snow that fell on Saturday. This previous snow remains dry on high elevation north facing slopes, while a 5 to 10 cm melt freeze crust can be found instead on all other aspects.
We're still tracking the April 4th crust which is down 20 to 80 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. We have not heard of any recent activity on this interface, but there is a question of whether forecast loading could reactivate in on high north aspects where it hasn't been capped by a crust.
Digging deeper, north facing alpine terrain also has a layer of facets down approximately 100 cm below the surface which are thought to be dormant at this time.
At lower elevations, ongoing warm weather has been promoting isothermal snowpack conditions and melting the snowpack away.
Problems
Storm Slabs
Ongoing snowfall has been building up fresh storm slabs at higher elevations, especially in lee areas where southerly winds have been able to redistribute new snow into thicker deposits. Slab depths are likely to increase with elevation.
- Look for signs of instability. Shooting cracks and recent avalanches indicate unstable conditions.
- Avoid freshly wind loaded features.
- Choose lower angled slopes away from overhead hazard while the new snow settles and stabilizes.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Apr 17th, 2019 2:00PM
