Avalanche Forecast
Issued: Apr 10th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Deep Persistent Slabs.
rgoddard,
Avalanche Canada
As the storm subsides, the snowpack will need some time to regain strength.
Make conservative decisions for the time being.
Summary
Confidence
Moderate
Avalanche Summary
Sunday saw an increase in avalanche activity as this most recent weather system touched down in our region. The primary cause of these avalanches were wind slabs and storm slabs with a couple of persistent slabs as well.
This persistent slab avalanche occurred on buried surface hoar down 30 cm. It was accidentally triggered on an east face and reached size 1.5.
With regard to the wind slabs, it is notable that several of these avalanches occurred on the western aspects and they slid easily on a solar crust that was formed early last week. One of these wind slab avalanches was accidentally triggered remotely in the alpine on a northeast aspect. The resulting size two avalanche which was 30 cm deep, ran 50 m. It carried one of the party members 40 m. They stayed on top of the avalanche but sustained a leg injury and had to be helicoptered out of the area.
Snowpack Summary
By Tuesday morning the highest elevations of our region will have storm snow totals reaching over 30 cm. 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 may exist.
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.
Weather Summary
Monday Night
Cloudy, 5 to 15 cm accumulation, winds southwest 15 to 25 km/h, freezing levels getting down to 1000 m.
Tuesday
Cloudy with potential late day clear periods, 5 to 10 cm accumulation, winds southwest 25 km/h, freezing levels to 1500 m.
Wednesday
Cloudy with sunny periods, 5 to 10 cm accumulation and 2 cm throughout the day, winds westerly 15 km/h, freezing level starting at 500 and climbing back up to 1500 m.
Thursday
Cloudy with sunny periods, trace accumulation, winds westerly 10 to 15 km/h, freezing levels starting at the valley bottom and climbing 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.
- Back off slopes as the surface becomes moist or wet with rising temperatures.
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
Problems
Storm Slabs
Precipitation amounts will begin to taper off later today. Warm temperatures will have this fall as rain at lower elevations and as heavy wet snow at higher elevations.
Whether it is rain, heavy snow, or a large wind deposit of snow, avalanche activity is expected to increase.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
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.
Likelihood
Expected Size
Valid until: Apr 11th, 2023 4:00PM
