Avalanche forecast

Haines Pass

Haines Avalanche Center
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Avalanche danger

Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Another low pressure system moves through today with a temperature increase that peaks mid-day at the height of today's storm. Expect sensitive slabs to get blown in from the south winds at and above treeline.  Identify and avoid these avalanche prone slopes that are getting loaded. Use patience and good group communications when making plans for terrain selection.

 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2

    You are most likely to trigger a recent slab from SE winds from today. These most recently formed wind and storm slabs are expected to be sensitive today with precipitation and warming temperatures. Look for shooting cracks, whumphing or collapsing that indicate unstable conditions. Lingering wind slabs may still exisit from the big storm Dec. 10-14th that brought strong south winds and 5.5" of snow water equivelent (SWE) to the Transitional Zone and 3" of SWE to the Chilkat Pass Zone.  NE-W alpine slopes should still be respected and avoided (see Persistent Slab problem below) and also Friday's NW winds.

    Natural D3 at 5,500' on a NE aspect of Flower

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3

    New snow from today is resting on surface hoar (SH) from Dec. 15th.  The distribution of the SH was observerved in the lower elevation band and is unknown at or above tree line. Seasonal weather history and snow profiles suggest potential for buried persistent weak layers. At the same time, there is a high uncertainty with lack of data on these PWLs. However, a widesspread natural avlanache cycle indicated  low uncertainy of instability during or following last week's storm with up to size 3 avalanches observed.

    (12/16/2023)

    Seasonal avalanche map shows distribution of recorded avalanches for aspect and elevations in the transitional and chilkat pass zones.

Avalanche Discussion

Recent dynamic weather during the Dec. 10-14th storm created a dynamic snowpack with a large natural avalanhce cycle. This was followed by the cold temps that pumped the brakes on improving stability immediately afterwards. With today a quick pulse of warm air, increased precipiation and south wind increase the avalanche hazard.  Move slow and smooth around avalanche slopes by practicing safe travel techniques and looking out for each other.

  • Numerous melt-freeze crusts and small grain facet layers have been identified across all zones. These remain worthy of future investigation and layer tracking.
  • Three calm, cold and clear periods in the weather produced surface hoar in protected, wind sheltered areas: Nov. 12th , Dec. 2nd, Dec. 10th, and Dec. 15th.
  • Early season hazards continue to exist, except now deep unconsolidated snow has hidden rocks, branches and logs. Use caution.
  • Help us make sense of what's going on out there by reading and submitting observations.

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