Avalanche Forecast
Issued: Apr 17th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Loose Wet and Deep Persistent Slabs.
lbaker,
Avalanche Canada
Remain cognizant that a weak, unpredictable layer continues to lurk near the bottom of the snowpack, avoid thin, rocky start zones and shallow areas with variable snowpack depths.
Avoid steep south facing slopes when the sun comes out.
Expect variable snowpack conditions as we transition from winter to spring.
Summary
Confidence
Moderate
Avalanche Summary
No new avalanches were reported before 4 pm on Monday.
On Friday, on the Meachen Falls & Hourglass FSR a large (size 2) wet loose avalanche ran nearly full path depositing a large debris pile on the access road. This avalanche was on a north aspect and was likely triggered during the daytime warming and solar input.
Avalanches from last week are being reported as people venture into the backcountry. Backcountry users have been reporting a widespread avalanche cycle, with numerous large (size 2) and some larger (size 3) avalanches. Mostly storm slabs in the alpine, and wet loose at treeline and below.
If you head out in the backcountry, let us know what you are seeing by submitting a report to the Mountain Information Network.
Snowpack Summary
Dynamic spring weather has resulted in variable snow surface conditions. A wet storm earlier in the week soaked the upper snowpack. Cold overnight temperatures have turned this moist snow into a frozen crust, except in areas where dry snow covered and insulated it.
The mid snowpack is generally settled and strong, except in areas with snow depths less than 150 cm. In these lower snow areas, the mid-pack is likely weaker and more faceted.
Below treeline, expect to find moist or refrozen surfaces, and a shrinking snowpack that is isothermal during the heat of the day.
The lower snowpack includes a layer of large, weak facets and/or depth hoar crystals.
Weather Summary
Monday Night
Cloudy increasing through the night. No new precipitation is forecast. Light southeast ridgetop wind. Freezing level around 1200 m. Treeline low around -3 °C .
Tuesday
Mainly cloudy with scattered flurries. 5-10 cm of snow is expected in the alpine. Light increasing to moderate southwest ridgetop wind. Freezing levels hover between 1600 and 1800 m. Treeline high around -1 °C
Wednesday
Mix of sun and cloud with isolated flurries, trace accumulations. Light west ridgetop wind. Freezing level at 1500 m. Treeline high around -1 °C.
Thursday
Partly cloudy with isolated flurries, 1-5 cm accumulations. Light west ridgetop wind. Freezing level at 1700 m. Treeline high around 0 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Be carefull around freshly wind loaded features.
- Watch for unstable snow on specific terrain features, especially when the snow is moist or wet.
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
Problems
Wind Slabs
New snow, combined with strong winds has built fresh windslabs in lees. Expect this problem to become sensitive to light triggers, once the temps rise. Human triggering remains possible on steep wind-loaded features.
Carefully evaluate for windslab hazard before committing to bigger features.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Loose Wet
During periods of daytime warming and sunshine, expect the surface snow to be unstable on slopes that face the sun.
A wet storm added a lot of moisture and heat to the upper snowpack earlier this week.
If you see signs of loose wet instability, like snow that feels like a slurpy, or clumps up and pinwheels down a slope, move to less steep and more shaded terrain.
Aspects: South East, South, South West, West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
The base of the snowpack remains weak. Avoid thin, rocky start zones and shallow areas with variable snowpack depths.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Apr 18th, 2023 4:00PM
