Avalanche Forecast
Issued: Apr 24th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Deep Persistent Slabs, Wind Slabs and Loose Wet.
mconlan,
Avalanche Canada
Sunny skies and a rising freezing level will increase avalanche danger during the heat of the day.
Summary
Confidence
Moderate
Avalanche Summary
Many small to large (size 1 to 2) wet loose avalanches were observed by riders over the weekend, generally occurring out of steep alpine terrain. We expect to see similar avalanches in the coming days during periods of sunny skies and an increasing freezing level.
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 week.
Use plenty of caution along alpine ridges, where cornices are likely large and weakening.
Snowpack Summary
Moist snow is found on all aspects up to 2200 m, which will freeze into a melt-freeze crust overnight. Dry snow may be found above 2200 m on northerly aspects, where wind slabs may linger in steep leeward slopes from southerly wind.
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. The likelihood of this layer being triggered will increase with each day of warming for the coming weeks. Humans are most likely to trigger it in steep and rocky slopes where the snowpack is relatively thin.
Cornices are large and looming at this time of year and will weaken with daytime warming.
Weather Summary
Monday Night
Mostly cloudy with no precipitation, 20 km/h southwest wind, treeline temperature -4 °C, freezing level 1400 m.
Tuesday
Early morning clouds then sunny skies with no precipitation, 10 to 20 km/h southwest wind, treeline temperature -3 °C, freezing level rising to 2000 m.
WednesdayMostly cloudy with trace snow or rain, 20 to 40 km/h southwest wind, treeline temperature 3 °C, freezing level 2400 m.
ThursdayMostly sunny with no precipitation, 10 km/h variable wind, treeline temperature 6 °C, freezing level 3500 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- 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.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
- Carefully evaluate steep lines for wind slabs.
- Use caution above cliffs and terrain traps where even small avalanches may have severe consequences.
Problems
Deep Persistent Slabs
The likelihood of very large avalanches releasing on a weak layer near the base of the snowpack will increase with each day of warming. Naturally triggered avalanches are most likely during the heat of the day. Human triggered avalanches are most likely in steep, shallow, and rocky terrain where the snowpack is relatively thin.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Wind Slabs
Wind slabs may linger on slopes above about 2200 m in lee terrain features from recent southwest wind. Assess for slabs prior to committing to any terrain with a potential high consequence.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Loose Wet
Wet loose avalanche activity is expected to continue during periods of strong sun and with daytime warming. Limit your exposure to steep terrain on sun-exposed slopes and when the snow starts feeling sloppy.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Apr 25th, 2023 4:00PM
