Avalanche Forecast
Issued: Mar 4th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Persistent Slabs and Deep Persistent Slabs.
ahanna,
Avalanche Canada
There is a high degree of variability through the region. Avalanche danger is highest in the north and west where a persistent weak layer is active and recent snow and wind have formed reactive wind slabs. In drier eastern areas, avalanche danger may be a step lower.
Summary
Confidence
Moderate - Uncertainty is due to extremely variable snowpack conditions reported through the region.
Weather Forecast
Wednesday night: Partly cloudy. Moderate southwest wind. Freezing level valley bottom.
Thursday: Mix of sun and cloud. Moderate southwest wind. Freezing level 1600 m.
Friday: 5-15 cm new snow. Light southwest wind. Freezing level 1500 m.
Saturday: 5-10 cm new snow. Light variable wind. Freezing level 400 m.
Avalanche Summary
Over the weekend and through Tuesday, natural and skier triggered wind slabs and cornices size 1-2 were observed on north to east aspects.
Persistent slab avalanche activity has been observed west of the region, were snowfall amounts have been greatest over the surface hoar layer. In this part of the region on Tuesday, skier accidental persistent slabs size 1-1.5 were reported on various aspects in wind affected areas around 2200 m. On the weekend, heli remotes were reported up to size 2.5 and natural persistent slabs size 2-3 were observed on south aspects around treeline.
Snowpack Summary
Light snowfall and strong winds are building fresh wind slabs in the alpine and open areas at treeline.
A weak layer of surface hoar sits 20-60 cm deep. Read more about surface hoar on our forecaster blog!
Deep basal facets lurk near the bottom of the snowpack. This layer has been responsible for sporadic deep persistent slab avalanches usually triggered from shallow, rocky start zones. No activity has been observed on these layers in the past week.
Terrain and Travel
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Shooting cracks, whumphs and recent avalanches are strong indicators of an unstable snowpack.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Problems
Wind Slabs
Incremental snowfall and strong winds are building fresh wind slabs in the alpine and open areas at treeline. Wind slabs will be deepest and most reactive in the north and west of the region. If triggered, windslabs have the potential to trigger deeper weak layers.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
A weak layer of surface hoar sits 20-60 cm deep. So far, the layer has been most reactive at treeline and alpine elevations in the deeper snowpack areas in the west of the forecast region. Where this layer exists, avalanche activity is expected to increase as it approaches critical loading by new snow and wind forecast later in the week. Read more about surface hoar on our forecaster blog!
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
Weak snow at the bottom of the snowpack continues to pose a deep persistent slab avalanche problem. Treat wind scoured, rocky, shallow terrain as suspect. Also avoid big alpine slopes that are threatened by cornices overhead.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 5th, 2020 5:00PM
