Avalanche Forecast
Issued: Apr 22nd, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Loose Wet.
bchristie,
Avalanche Canada
Consider starting with small slopes in simple terrain, and watch how the surface snow is changing through the day. A wet and dynamic storm could bring rapid change to the snowpack.
The biggest concerns are fresh storm slabs in the alpine, and rain soaking any dry snow that remains at treeline and below.
Summary
Confidence
Avalanche Summary
On Saturday in the Coquihalla area, daytime warming caused numerous naturally triggered wet loose avalanches in steep terrain. The largest of these avalanches was a size 2.
Looking forward, similar wet loose avalanches could continue while it rains at and below treeline. Also, new snow and moderate southwest wind at treeline and above mean wind slabs could be triggered by riders in lee terrain features.
Use plenty of caution along alpine ridges, where cornices may be large.
Snowpack Summary
15 to 20 cm of new snow in the alpine and into upper treeline. Moderate southwest wind building fresh windslab on the existing windslab, or on a breakable crust on solar aspects.
Below treeline, a mix of rain and snow will be falling on a variety of moist or frozen surfaces.
The remainder of the snowpack is strong with varying hard snow layers and bonded melt-freeze crusts. Cornices are large along many alpine ridges.
Weather Summary
The rain/snow amounts below represent the west side of the forecast area. The forecasted precipitation amounts are much lower east of the Coquihalla summit and Allison Pass.
Saturday Night
Cloudy. Light to moderate snow/rain, 5 to 10 mm. Chance of freezing rain. Snow/rain line around 1400 m. Treeline low around 0°C. Light to moderate south or southwest ridgetop wind.
Sunday
Cloudy. Moderate snow/rain, 8-12 mm. Snow/rain line between 1250 and 1500 m. Treeline low around -1°C. Moderate southwest ridgetop wind.
Monday
Low cloud. Light snow/rain expected overnight and through the day, 5-15 mm. Snow/rain line rising from 1000 to 1500 m. Light west or southwest ridgetop wind.
Tuesday
Mostly sunny by the afternoon. Trace of snow/rain expected. Freezing level rising to between 1800 and 2200 m. Light west or southwest ridgetop wind.
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.
- Watch for unstable snow on specific terrain features, especially when the snow is moist or wet.
- Use ridges or ribs to avoid areas of wind loaded snow.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
Problems
Wind Slabs
Recent snow from Thursday night continues to be redistributed by moderate southwest wind. Assess for slab development before committing to large terrain features.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Loose Wet
The most problematic elevation is likely around treeline, where recent dry snow is getting hit by rain for the first time.
Wet loose avalanches may be less likely at low elevations, where most of the snowpack has already experienced several heavy rainfalls and significant warming, but if you are finding, deep, slushy, loose snow, use extra caution on steep slopes.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Valid until: Apr 23rd, 2023 4:00PM
