Avalanche Forecast
Issued: Mar 25th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Persistent Slabs and Cornices.
TRettie,
Avalanche Canada
Carefully assess steep lines for wind slabs and limit exposure to cornices. We have some uncertainty in the likelihood of triggering persistent slab avalanches.
Summary
Confidence
Moderate - Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast.
Weather Forecast
Friday night: Possibility of light flurries bringing trace amounts of new snow with light east winds. Low of -2 at 900 m.
Saturday: Flurries bringing around 5 cm. Light to moderate southeast wind. Freezing level 1100 m.
Sunday: A mix of sun and cloud with the possibility of light flurries bringing trace amounts of new snow. Light variable winds. Freezing levels rising to 1400 m.
Monday: Sunny with no new snow expected and light west winds. Freezing level rising to 1500 m.
Avalanche Summary
On Thursday a size three natural persistent slab avalanche was reported . This avalanche ran on the mid March surface hoar layer. It was at 1600 m on a northeast aspect. Several natural and explosive triggered cornice falls up to size three were also reported throughout the region. Natural and explosive triggered wind slabs were observed to size 1.5.
Touchy avalanche conditions on Wednesday saw skiers and machines remotely triggering storm slabs size 1.5-2. We're scratching our heads over a report from near Ningunsaw of a skier-triggered size 2.5 and sympathetic size 2 deep persistent slab. The avalanches occurred on a west aspect around 1200 m and crown depths varied from 40 cm to 120 cm.
Snowpack Summary
30-50 cm of recent snow has seen variable wind effect at upper elevations. Below 1500 m, recent snow tapers in depth and sits over a wet or crusty upper snowpack.
A weak layer of surface hoar from mid March buried 70-120 cm deep has become more difficult to trigger but recent avalanche observations indicate that it may continue to be problematic.Â
A thick rain crust from mid-February 130-200 cm deep caps a well consolidated lower snowpack.
Terrain and Travel
- Be especially cautious as you transition into wind affected terrain.
- Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.
- Be aware of the potential for large avalanches due to the presence of a persistent slab.
- When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.
Problems
Wind Slabs
Sensitivity to triggering wind slabs could be greater where wind slab has formed over surface hoar or a crust. If triggered, wind slab avalanches have potential to step down to deeper layers.
Aspects: North, North East, East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
We have uncertainty as to whether a layer of surface hoar buried 70-120 cm deep remains a problem. While it is now likely too deep to be easily triggered by riders, it may remain triggerable by large loads such as cornices and avalanches.
Aspects: North, North East, East.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Cornices
Limit exposure to cornices. Cornice falls can trigger large avalanches on the slopes below.
Aspects: North, North East, East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Mar 26th, 2022 4:00PM
