Avalanche Forecast
Issued: Apr 18th, 2019 3:51PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
cgarritty,
Avalanche Canada
Snowfall and winds have been steady, but field observations are scant. Use this forecast as your starting point and gather information about the depth and reactivity of new snow as you travel. ..then post your observations to the MIN!
Summary
Confidence
Moderate - Due to the number of field observations
Weather Forecast
Thursday night: Mainly cloudy with isolated flurries and a trace of new snow. Light to moderate southwest winds.
Friday: A mix of sun and cloud with isolated flurries and a trace of new snow. Light to moderate west winds. Alpine high temperatures around -3 with freezing levels to 1000 metres.
Saturday: Mainly sunny. Light south winds. Alpine high temperatures around -1 with freezing levels to 1300 metres.
Sunday: A mix of sun and cloud. Light south winds. Alpine high temperatures around 0 with freezing levels to 1500 metres.
Avalanche Summary
No new avalanches have been reported in the region. However, dangerous avalanche conditions are likely to exist at higher elevations where loading from new snow and wind have been building reactive new wind slabs.
Snowpack Summary
Approximately 10 cm of new snow is expected to accumulate on the surface at higher elevations on Thursday night, bringing new snow totals since Tuesday to approximately 20-40 cm. Strong southwest winds are expected to have formed reactive wind slabs with the new snow over Wednesday night and Thursday.
The new snow has buried another 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.
The April 4th crust is now down 30 to 100 cm on high elevation north facing slopes. Surface hoar and facets were previously observed on this crust and it recently produced sudden results in snowpack tests. We have not heard of any recent activity on this interface, but there is a question of whether loading could reactivate in on high north aspects where it hasn't been capped by a crust.
At lower elevations, ongoing warm weather has been promoting isothermal snowpack conditions and melting the snowpack away.
Problems
Wind Slabs
Strong winds likely packed much of our recent snow into fresh wind slabs, especially on lee (north to east) slopes. This problem increases with elevation and proximity to the coast. Slabs that formed over crust at the previous surface may be touchy.
- Avoid freshly wind loaded features. Thicker, touchier slabs are likely on north through east aspects
- Look for signs of instability. Shooting cracks and recent avalanches indicate unstable conditions.
- Evaluate the bond and reactivity of recent snow to the old surface before committing to your line.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Apr 19th, 2019 2:00PM
