Avalanche Forecast
Issued: Apr 27th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Deep Persistent Slabs and Cornices.
mconlan,
Avalanche Canada
Travel cautiously and expect to find wind slabs in steep terrain. The possibility remains of triggering buried weak layers. For more information about the incoming warming, check out the latest Forecasters' Blog.
Summary
Confidence
Moderate
Avalanche Summary
We haven't received any recent avalanche observations. Going forward, we expect that riders could trigger wind slabs in steep terrain features and potentially storm slabs in steep wind-sheltered terrain.
The likelihood of triggering a buried weak layer will increase as the freezing level rises on the weekend. Wet loose avalanches are also possible during any period of sunny skies.
Avoiding cornice exposure is also a good idea, as they are very large and could fail naturally or under the weight of a human.
Snowpack Summary
Wind slabs may be found in steep, lee terrain features from recent snow and strong southerly wind. Storm slabs could prevail in wind-sheltered terrain. These slabs may sit on a hard melt-freeze crust found up to 1400 m and to mountain tops on sun-exposed slopes. The snow surface could moisten on sun-exposed slopes during periods of sunny skies.
A weak layer of facets and potentially a melt-freeze crust from early January is buried over 100 cm deep in most areas.
Weak faceted grains may exist near the base of the snowpack, particularly in shallower snowpack areas.
Cornices are very large and looming along alpine ridges.
Weather Summary
A mix of sun and cloud and isolated flurries is forecast for the coming days, with a freezing level around 1300 m for Friday, up to 2300 m for Saturday, and dropping back to 1500 m for Sunday. The wind is expected to remain moderate to strong from the south.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
- Cornice failure may trigger large avalanches.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
- Even brief periods of direct sun could produce natural avalanches.
Problems
Wind Slabs
Snow and strong wind have likely formed new wind slabs in lee terrain features. Also use caution in wind-sheltered terrain, where storm slabs could be found. Assess for slabs in steep terrain before committing yourself.
Aspects: North, North East, East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
Weak layers may be found in the middle and near the base of the snowpack, which are likely to reawaken with the variety of weather we receive during the spring. Small avalanches and cornice falls have the potential to trigger these deeper layers. Human triggered avalanches are most likely in steep, shallow, and rocky terrain where the snowpack is relatively thin.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Cornices
Cornices are large at this time of year and will become more prone to fail as they warm up with spring weather. Stay well back from them when on ridgelines and limit your exposure when travelling on slopes below them, as their release is unpredictable. Cornice falls could trigger very large slab avalanches on slopes below.
Wet loose avalanche activity is also expected with periods of strong sun. Limit your exposure to steep terrain when the snow moistens.
Aspects: North, North East, East, West, North West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Apr 28th, 2023 4:00PM
