Issued: Apr 10th, 2023 4:00PM
The alpine rating is Storm Slabs and Deep Persistent Slabs., the treeline rating is , and the below treeline rating is Known problems include
Forecasted weather will bring heavy precipitation and strong winds to much of our region and will increase the avalanche hazard.
The chance of avalanches is very likely today.
Make conservative choices and back off if you see signs of instability.
Sunday saw an increase in avalanche activity as this most recent weather system touched down in our region. These avalanches were caused by wind slabs and storm slabs.
The wind slabs were triggered naturally, by ski cuts, and by cornice failure. They reached up to size two and were 35 to 40 cm deep when they started. All were in the alpine on a variety of aspects including cross-loaded terrain.
By Tuesday evening up to 60 mm will have fallen in a 36-hour period. Due to recent high freezing levels much of this fell as moist heavy snow or rain. Expect wind slabs to have formed from southwest winds where snow was light enough to be transported.
On southerly aspects and below treeline, there is a widespread cust buried 30 to 50 cm down. On north-facing slopes at treeline and above there may exist a layer of faceted snow or surface hoar in shelter areas. Further down in the snowpack, around 60 cm, a surface hoar layer has been reactive to human triggering. This has occurred primarily in the Selkirks, on northeasterly slopes from 1700 m to 2100 m. Wednesday was the last day that there was any real activity on this layer but this storm may change that.
The mid-snowpack is generally strong but the lower snowpack is a different story. The November facets are still prominent at the base of the snowpack. This layer remains a concern in rocky, shallow, or thin to thick snowpack areas at treeline and above.
Cloudy, 25 to 30 cm accumulation of wet snow, winds southwest 20 to 30 km/h gusting to 50, freezing levels cooling to 1600 m.
Cloudy, 20 to 30 cm accumulation, winds southwest 30 to 40 km/h, freezing levels 1500 m.
Cloudy with sunny breaks, up to 10 cm accumulation by morning, winds west 15 km/h, freezing levels starting at 500 m and climbing to 1500 m.
Cloudy with sunny periods, trace accumulation, winds west 10 to 20 km/h, freezing levels climbing back up to 1600 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Continue to make conservative terrain choices while the storm snow settles and stabilizes.
- Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
- Seek out sheltered terrain where new snow hasn't been wind-affected.
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
- The more the snow feels like a slurpy, the more likely loose wet avalanches will become.
- Caution around slopes that are exposed to cornices overhead.
Significant precipitation continues to hammer our region. Warm temperatures will have this fall as rain at lower elevations and as heavy wet snow at higher elevations. Moderate to strong southwest winds all also associated with this storm.
Aspects: All aspects.
Elevations: All elevations.
Deep Persistent Slabs
A weak layer of facets exists near the base of the snowpack. The likelihood of human triggering is low given the layer's depth.
Suspect terrain for human triggering includes steep, shallow, and rocky terrain where the snowpack transitions from thin to thick.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Valid until: Apr 11th, 2023 4:00PM