Bollettino valanghe

San Francisco Peaks / Kachina Peaks Wilderness

Kachina Peaks Avalanche Center
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Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 3 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Wind slab will continue to be the primary problem of the day.  Expect to find recent loading and possibly reactive wind slabs-which could carry or even bury an individual--on the leeward side of ridgelines, in loading zones, on cross-loaded ridges, and even in some open clearings.  Watch for cracking and avoid steep wind loaded areas, especially those above cliffs, trees, and other hazardous terrain features.

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Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2

    Over the last couple of days, southwest and west winds created reactive wind slabs on leeward slopes and terrain features. While winds calmed on Friday morning, by late afternoon they increased in velocity and shifted to the Northwest, loading new snow on South to East aspects.  Overnight 2-4" of snow is expected, creating even more snow available for wind transport by moderate gusts.  Anticipate human triggered wind slab avalanches to be likely throughout the day, especially with the forecast winds. Avoid wind-loaded, rounded, pillowed, wind drifted waves, or corniced slopes, as these may harbor sensitive slabs that could release under the weight of a skier.  

    On Friday, an R2-D2 avalanche was triggered while a party was assessing a north-facing slope near the Humphreys Trail Saddle. The avalanche propagated when an individual was ski-cutting while belayed by a partner. The avalanche crown was 6-24" and was ~200 feet wide.  Additionally, smaller wind slab releases were reported on steep west and northeast aspects near treeline. 

    (3/24/2023) Wind slab avalanche on north aspect near Humphreys Trail Saddle at ~11,800'. Crown was 6-24" and ~200' in total (red arrows). Crown line extended behind (west) where the image was taken.

Avalanche Discussion

The snowpack from last week's large storm seems to be settling and bonding.   The most talked about issue has been the release of several small to large wind slabs near and above treeline, primarily occurring on Friday.  This trend is likely to be steady.  Most near and above treeline windslab likely bonded some today, but the shift in wind direction, from the northwest, and the deposition of additional snow yesterday afternoon and last night, will keep this problem likely.  Reports on above treeline conditions have been scarce the past couple of days as limited visibility has made touring above treeline difficult.  Moderate winds are forecast for the day and gusts will likely continue to actively load the leeward side of ridges and terrain features.  Use good sense when traveling above treeline and on exposed ridgelines--don't be afraid to retreat, especially on slopes approached from the top down.  Avoid areas where wind has accumulated snow into cornices, piles, and pillows.  Specifically, the main ridgeline and surrounding connective ridges between Humphrey's and Agassiz could contain wind slabs which may release under the weight of a single individual.

In addition to the wind slab issue, backcountry travelers should be aware that the snowpack is currently quite variable based on aspect and elevation.  The sun has already started to bake southwest through Southeast slopes.   A number of crusts and possible near surface facet layers are present in the top meter of the snowpack.  Yesterday on a Southwest facing aspect at 11,600 feet an ECTP23 was reported at 61 cm from the top and in a pit dug on Thursday, there was propagation at the same layer.  If an avalanche fails on these layers, it could be much larger than you may expect and could be unsurvivable.

Several folks have mentioned that this is the best coverage they have ever seen in 25-45 years of touring around Flagstaff. It's been an amazing year with no reported backcountry injuries or burials. Backcountry touring is a special activity, but it is serious business. Stay diligent and aware. Remember to use good avalanche travel techniques within your group, only exposing one person at a time to avalanche terrain. But also remember that backcountry usage has increased on the Peaks and other groups could be above or below you. With this, it is especially important to consider other groups' possible travel plans while in complex and steep terrain.

SupportIf every person that reads our forecast page donated just $10/year, then KPAC would be fully funded and could grow, providing daily forecast updates all season. https://kachinapeaks.org/Support

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