Avalanche forecast

Northwest Coastal

Apr 2 – 3, 2014Avalanche Canada
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Avalanche danger

Fri
Sat
Alpine
4 · High
Treeline
4 · High
Below
3 · Considerable
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Highlights

Avalanche hazard will likely increase throughout the day, be sure your plans allow for a safe retreat from the mountains.

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–4
    New snow accompanied by strong wind should result in new slabs being formed on top of surface hoar and crusts beginning Wednesday night. I expect these touchy slabs will become more and more problematic as the day goes on Thursday.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    3–7
    Two buried weak layers exist in the snowpack. These weak layers could be activated by cornice fall, a smaller surface avalanche in motion, or a rider finding the sweet spot, which would be most likely in steep rocky terrain.

Weather Forecast

Synopsis: A series of relatively weak systems should deliver daily precipitation through the weekend. There is potential for a very potent storm early next week, but its still way too early to count on.Wednesday Night: Precipitation: 2:7mm - 3:10cmThursday: Freezing Level: 700m - 1100m; Precipitation: 2:10mm - 2:15cm; Wind: Treeline: Moderate, S/SW | Ridgetop: Strong, SWFriday: Freezing Level: 800m - 1200m Precipitation: Trace; Wind: Treeline: Light, SW | Ridgetop: Moderate, WSaturday: Freezing Level: 1100m - 1400m; Precipitation: 1:8mm - 2:13cm; Wind: Treeline: Light, S | Ridgetop: Strong, SW

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain

Avalanche Summary

On Tuesday there was one report of a remotely triggered size 2 wind slab avalanche on a NE facing aspect at 1500m. This location had previously slid on the early February crust/facet/surface hoar combo. Isolated loose wet avalanches to size 1.5 were also reported from steep southerly terrain.On Monday. A large rock fall event initiated a size 3.5 avalanche that failed on the early February persistent weak layer. Several smaller loose snow avalanches to size 2 were running in the recent storm snow on steep solar aspects too.

Snowpack Summary

It's starting to feel like spring in the NW. Valley temps are creeping into the double digits during the day, and there are reports of the top 15 cm of the snowpack becoming moist during daytime heating.The last significant shot of snow was on March 27th, 10 - 15 fell on March 30th. This new snow rests on top of a haggard old surface composed of old wind slab, melt freeze crust, and faceted old snow. Ongoing melt freeze cycles will likely help to heal any surface instabilities.The early March layer can be found down 75 - 100cm and is composed of facets/surface hoar on shady aspects and facets/crust on southerly aspects. I suspect this layer has been the culprit in the human triggered avalanches from March 27/28 that are being reported on the Balktalk Facebook Page.The early February crust/facet/surface hoar combo is down 150 - 200cm, and I suspect it's gone mostly dormant for now.

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