Avalanche forecast

Purcells

Jan 9 – 10, 2012Avalanche Canada
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Archived · expired 15 years ago

Avalanche danger

Wed
Thu
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2–6
    Activity has slowed, but hard slabs capable of breaking above you still exist & are most prevalent immediately lee of ridge crests as well as midslope on crossloaded features. Watch for fresh slab formation as winds switch to the NW Mon. night/ Tue.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    3–7
    A deep cohesive slab rests on a surface hoar weakness buried mid-Dec. This layer is still susceptible to rider triggering. If it goes, it will likely propagate across surprisingly large distances producing a deep & destructive avalanche.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    5–8
    Very weak snow near the ground is right on the cusp of being a problem. Avoid areas where the snowpack goes from thick to thin as well as likely trigger points such as rock outcroppings.

Confidence

Fair - Due to variable snopack conditions

Weather Forecast

A weakening cold front associated with the big weekend storm slides across the region Monday night persisting into Tuesday. The Purcell's will receive light precipitation out of the system; I'm not expecting more than 10 cm by the end of the day Tuesday. A ridge of high pressure builds in Tuesday afternoon bringing dry conditions and lowering freezing levels down to valley bottom by Tuesday evening. Moderate to strong winds will be blowing out of the NW Tuesday in exposed locations. Expect a daytime high of -6 with an overnight low of -9 @ 1500m. Wednesday looks to be cool and dry with no precipitation expected.

Avalanche Summary

A skier was killed in a size 3 avalanche in the Molar area of the Dogtooth range near Golden on Friday. The 4th skiers on the slope triggered the slide. On Saturday a skier triggered a size 3 avalanche in the alpine, the crown averaged 100cm in depth & the avalanche was reported to have run full path. The group had been skiing in the area all day without result until the accident happened. Avalanche activity on Sunday was confined to operational explosive use & produced avalanches to Size 2 on high elevation NE facing slopes.

Snowpack Summary

The latest batch of storms has delivered around 50 cm of snow to the region. In some locations the new snow rests on top of a surface hoar layer buried January 3rd. Strong southwesterly winds have redistributed the new snow into windslabs that can be found on NW through SE facing slopes at and above treeline. Widespread crossloading is present throughout the region. A rain / melt/freeze crust formed by recent warm temperatures can be found as high as 1600m. The mid-December surface hoar layer continues to be a player, it's now buried 80 - 140 cm below the snow surface. Very weak snow near the ground is also a concern and while it has not been reactive recently, triggering a full depth avalanche near the ground is within the realm of possibilities right now.

Regions covered