Avalanche Forecast
Issued: Mar 2nd, 2020 5:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
astclair,
Avalanche Canada
Strong winds and new snow continue to build wind slabs at upper elevations. Deeper instabilities cannot yet be discounted.
Summary
Confidence
Weather Forecast
Monday night: Cloudy, 5-10 cm of snow, strong west winds becoming northwest, freezing level rising to 1200 m.
Tuesday: Cloudy, up to 5 cm of snow, moderate southwest winds gusting to strong, freezing level 1100 m.
Wednesday: Mix of sun and cloud, 5-15 cm of snow overnight, west winds decreasing to light, freezing level below 800 m.
Thursday: Cloudy, 20-30 cm of snow, strong southwest winds, freezing level 1000 m.
Avalanche Summary
No new avalanche observations have been reported.
Snowpack Summary
Up to 15 cm of new snow and strong winds from the west are expected to continue to build reactive wind slabs at upper elevations.
40-70 cm of recent snow may overlie a layer of surface hoar on north-facing aspects near and above treeline, and observers have reported reactivity in snowpack tests. See this MIN for a helpful illustration. Surface hoar is an exceptionally weak layer not often seen in this region, and it typically takes longer to heal. This persistent weak layer warrants investigation and a conservative terrain use strategy. Check out the latest forecaster blog that offers a deeper dive into these conditions.
The remainder of the snowpack is well settled. Depth varies from around 250 to 300 cm at the peaks of the North Shore mountains (1400 m), tapering rapidly with elevation.
Terrain and Travel
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
- Be aware of the potential for large avalanches due to the presence of buried surface hoar.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
Problems
Wind Slabs
New snow and strong west winds are expected to continue to build reactive wind slabs on lee features at upper elevations. These areas of concern overlap with where cornices may also be reaching their breaking point.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
A weak layer of feathery surface hoar may be found 40-70 cm deep on north-facing aspects near and above treeline. A persistent slab problem is not typical for the South Coast, and there is high uncertainty with regard to how quickly it will heal. Reduce this uncertainty by investigating these deeper layers if you are travelling near steep, open slopes at upper elevations.
Aspects: North, North East, East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 3rd, 2020 3:00PM
