Avalanche forecast

Sea To Sky

Jan 21 – 22, 2016Avalanche Canada
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Avalanche danger

Sat
Sun
Alpine
4 · High
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Wait a couple days to gather more post-storm information before venturing out into bigger terrain.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–5
    Thursday's storm may have helped clean out the mid-January surface hoar problem; however, wait a day or two to reassess the conditions before moving out into steeper terrain. 

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely - Very Likely
    Size
    1–4
    Continued snowfall on Thursday night at higher elevations may prolong the storm slab problem. Watch for deep and touchy wind slabs in lee (NW-NE) and cross-loaded terrain.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3
    Loose wet sluffs are possible in steep open terrain below treeline where precipitation persists as rain on Friday morning.

Confidence

Moderate - Freezing levels are uncertain

Weather Forecast

Tonight and Friday: Rain or snow ending in the morning (20-30 mm), then cloudy. The freezing level dips from 2000 m to 1400 m. Winds are moderate SE easing to light from the SW. Saturday: Cloudy with sunny breaks. The freezing level is around 1200 m and winds remain light from the W-SW. Sunday: Cloudy with sunny breaks. The freezing level is around 1000 m and winds are light from the S-SW.

Avalanche Summary

We will have to wait a day or two to determine how extensive the avalanche cycle on Thursday was. My guess is that we saw widespread activity at all elevations with slides up to at least size 3. Natural activity should taper off heading into the weekend. Hopefully the buried surface hoar problems were cleaned out, but I would treat any slope that did not release as being suspect, especially at treeline.

Snowpack Summary

The upper snowpack may look quite different after Thursday's storm. Expect dense new wind and storm slabs, and fresh cornice growth at upper elevations. Heavy loading from snow (and potentially rain) may have flushed-out the mid- and early-January surface hoar/facet layers that were buried 60-100 cm deep. However, don't rule these layers out right away. It may still be possible to trigger shallow slopes that did not release naturally. Rain has probably saturated the upper snowpack on lower elevation slopes (below 1500-1800 m).The mid and lower snowpack is generally strong, with the exception of shallower snowpack areas that may be more faceted.

Regions covered