Avalanche forecast

South Coast

Apr 1 – 2, 2014Avalanche Canada
View on map
Archived · expired 13 years ago

Avalanche danger

Thu
Fri
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
Open full map

Highlights

Use increased caution during afternoon warming, especially on sun exposed slopes.

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–4
    Watch for wind slabs immediately lee of ridge crest that may still be sensitive to human triggering. The strong spring sun has the potential to initiate both small loose and large storm slab avalanche activity on all aspects.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    3–6
    Two deep weak layers exist in the snowpack. These weak layers could be activated by warming temps, cornice fall, a smaller avalanche in motion, or a rider finding the sweet spot.

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Wednesday

Weather Forecast

Synopsis: The South Coast should remain mostly dry under the ridge of high pressure until Thursday evening when a more potent front makes landfall.Wednesday: Freezing Level: 1400m - 1700m; Precipitation: Nil; Wind: Treeline: Light, Variable | Ridgetop: Moderate, NWThursday: Freezing Level: 1100m - 1600m; Precipitation: Trace; Wind: Treeline: Light, S | Ridgetop: Moderate, SWFriday: Freezing Level: 1100 - 1800m; Precipitation: 1:10mm - 1:15cm; Wind: Treeline: Moderate, SW | Ridgetop: Strong W/SW

Avalanche Summary

Warming temps drove a natural avalanche cycle to size 3 on Monday. It's important to note that many of these large avalanches were running on shady N-NE facing slopes between 1900 and 2500m. Included in this cycle was a size 3 at 2500m on a steep north facing slope that is suspected to have released on one of the deep persistent weak layers. Several smaller loose snow avalanches to size 2 were running in the recent storm snow on all aspects too.

Snowpack Summary

The weekend storm produced 30 to 50cm in the north and around 30 cm in the south. Mild temperatures and solar radiation on Monday/Tuesday are likely causing settlement of the storm snow and melting of the snow surface on most slopes expect maybe steep north aspects in the alpine. This settlement is helping this snow to bond to the underlying melt freeze crust that exists below 2100m, on all aspects with the exception being north facing terrain above 1500m where the crust is not present. The first part of the storm was accompanied by strong southerly winds that formed isolated wind slabs immediately below ridge crest.The persistent weak layers from early March and early February continue to be a concern. The March melt-freeze crust/surface hoar is reported to be down 60 - 100cm. The February crust/facet/surface hoar layer is now deeply buried down 150 - 250cm and may still be triggered by heavy loads like cornice falls or storm slab avalanches in motion. Avalanches releasing on these layers may step down to the ground during periods of strong solar radiation or warm spring rain.

Regions covered