Avalanche Forecast
Issued: Apr 26th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Cornices, Deep Persistent Slabs and Loose Wet.
mconlan,
Avalanche Canada
A very high freezing level will destabilize the snowpack, potentially triggering numerous different avalanche problems. Check out the latest Forecasters' Blog for more information.
Summary
Confidence
Moderate
Avalanche Summary
Riders should expect wet loose avalanches and cornice failures during periods of warm air and sunny skies. Avoiding steep slopes when the snow feels sloppy and avoiding cornice exposure are good travel habits.
The likelihood of seeing very large avalanches releasing on the buried weak layer described in the Snowpack Summary will increase with each day of warming. This is particularly true for days without an overnight surface refreeze. Humans are most likely to trigger this layer in steep and rocky slopes where the snowpack is relatively thin.
Snowpack Summary
The snow surface is moist to mountain tops, which may or may not freeze into a melt-freeze crust overnight.
The middle of the snowpack is consolidated with various layers of moist snow, hard snow, and melt-freeze crusts.
A layer of weak faceted grains is found near the base of the snowpack at treeline and alpine elevations.
Cornices are large and looming at this time of year and will weaken with daytime warming.
Weather Summary
A ridge of high pressure will bring mostly sunny skies and freezing levels between 3500 m and 4000 m between Thursday and Saturday.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
- Cornice failures could trigger very large and destructive avalanches.
- The likelihood of deep persistent slab avalanches will increase with each day of warm weather.
- A moist or wet snow surface, pinwheeling and natural avalanches are all indicators of a weakening snowpack.
- The more the snowpack warms-up and weakens, the more conservative you`ll want to be with your terrain selection.
Problems
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. Remember that a flat spot on a ridgeline could be an overhanging cornice. Cornice falls could trigger very large slab avalanches on slopes below them.
Aspects: North, North East, East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
The likelihood of very large avalanches releasing on a weak layer buried near the base of the snowpack will increase with each day of warming. Human triggered avalanches are most likely in steep, shallow, and rocky terrain where the snowpack is relatively thin. Naturally triggered avalanches could occur without warning and are most likely on days when there isn't a good overnight refreeze. Resulting avalanches could travel far and even into snow-free valleys. For this reason, recognizing and avoiding areas with large overhead avalanche slopes, even if they are out of sight, is very important.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Loose Wet
Wet loose avalanche activity is expected with daytime warming and during periods of strong sun. This problem can quickly change over the day. Stable conditions in the morning can turn very unstable during the heat of the day. Limit your exposure to steep terrain when the snow feels sloppy.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Apr 27th, 2023 4:00PM
