Avalanche Forecast
Issued: Mar 23rd, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Cornices.
ahanna,
Avalanche Canada
Caution around cornices and wind slabs at elevations with dry snow.
Summary
Confidence
Moderate - Uncertainty is due to field data and reports showing a wide variation in conditions throughout the region.
Weather Forecast
Wednesday night: A trace of snow. Moderate southwest wind. Alpine low around -8 °C. Freezing level dropping to valley bottom.Â
Thursday: A mix of sun and cloud. Moderate southeast wind. Alpine high around -6 °C. Freezing level 1100 m.
Friday: Cloudy with sunny periods. Light south wind. Alpine high around -5 °C. Freezing level 1100 m.
Saturday: Mostly cloudy. Moderate southeast wind. Alpine high around -5 °C. Freezing level 1100 m.
Avalanche Summary
Reports from Tuesday and Wednesday indicate limited avalanche activity during the rain event. A few loose wet avalanches were reported up to size 1.5 at 1800 m and lower. Over the last three days size 1.5-3 avalanches have resulted from natural cornice failures triggering wind slabs on slopes below.
Persistent slab avalanches on a weak layer of surface hoar crystals buried in late February surprised a few people last week with accidental and remote triggers. The layer was most active on north-northeast aspects between 1200 and 1600 m in areas north of Hazelton. This problem has likely become more difficult to trigger as a bridging crust forms over wet surface snow.
Snowpack Summary
Wet snow or crusty conditions can be found at least as high as 1700 m. Wind slabs may be found at high elevations that have remained dry.
A couple of layers of weak crystals in the upper snowpack appear to be bonding. Our field team's latest snowpack tests produced no results at these interfaces. Additionally, we suspect that the surface crust will help bridge these layers, further decreasing their likelihood of triggering.
A thick crust formed in mid-February is now buried 50-80 cm deep. It is unlikely to present an avalanche problem under the current conditions and in fact bridges any underlying instabilities in the lower snowpack.
Terrain and Travel
- A crust on the surface will help bind the snow together, but may make for tough travel conditions.
- Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
- Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.
Problems
Wind Slabs
Wind slabs likely remain triggerable at elevations where the snow has remained dry. Watch for drifted or wind loaded snow in leeward terrain features with sharp changes in slope angle like ridge crests, ribs and convexities.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Cornices
Cornices have undergone rapid growth. Recently reported cornice failures have triggered wind slabs on slopes below.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Mar 24th, 2022 4:00PM
