Avalanche forecast

San Francisco Peaks / Kachina Peaks Wilderness

Kachina Peaks Avalanche Center
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Avalanche danger

Thu
Alpine
4 · High
Treeline
4 · High
Below
3 · Considerable
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Out of date — this forecast expired 3 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

In just 24 hours, slopes have been loaded with as much as 24" of new snow.  Conditions are dangerous, human-triggered avalanches are very likely, and natural avalanches are likely.  Stay out of near and above treeline terrain, and in openings amongst the trees, watch for wind loaded areas.

As this storm continues, expect the possibility of a natural avalanche cycle with large and maybe very large avalanches.  

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    1–2.5

    Existing weak layers are likely to become active as this storm continues to load the snowpack.  Two primary persistent weak layers are of concern: one at the bottom of the snowpack and another at what was once the mid-level layer.  In areas where these are sufficiently loaded, human-triggered avalanches are very likely and natural avalanches are likely. Today, avoid near and above treeline terrain.  

    In terms of rates, 18" of snow was deposited at 10,800 feet in just 12 hours, and the Snowslide Canyon Snotell has received 2.7" of SWE in the last 24 hours.  Where this snow has been distributed across starting zones, large to very large avalanches are possible. These can completely bury any skier or rider, and release without warning.

    (2/4/2024)

  • Wind Slabs

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

    Winds were active yesterday and throughout the evening, shifting in multiple directions, particularly at higher elevations.  Large wind slabs may be present in some locations across the upper mountain, in areas such as cross-loaded gullies and starting zones.  These wind slabs could step-down and release persistent slab avalanches buried deeper in the snowpack.  Avoid wind drifts and large areas of mounded and pillowed snow.

    At below treeline elevations it is possible that some small, thin, soft to hard wind slabs are present.  Watch for and avoid wind loading in small open areas and across gullies and the leeward side of ridgelines.  Hollow-sounding slabs and shooting cracks are sure signs of instability.  Below treeline, these avalanches will likely be small but could partially bury a skier or rider.  Small terrain features such as gullies or abrupt flat areas could deepen burials.  Travel cautiously and with a partner, even if navigating treed terrain.  

Avalanche Discussion

The Winter Storm Warning has been extended into Thursday morning as two more pulses of precipitation approach the region.  These storms will further load the snowpack creating increasing hazard throughout the day.  Yesterday, the snow stake at 10,800 received 18" of snow in a 12-hour period.  Overnight, 8 additional inches were recorded, bringing the total to 26".  At the Snowslide Canyon site, 19" was recorded with 2.7" of SWE in a 24-hour period.  This rapid loading will likely disagree with the existing snowpack and result in a natural avalanche cycle that could have started as early as last night.

This is our first large weather event of the year, and existing weak layers in the snowpack are the primary concern as the storm continues to impact Northern Arizona.  Two primary persistent weak layers are present and will probably result in natural avalanches during and just after the storm.  The first and most prominent of these layers is a set of basal facets and depth hoar buried at the bottom of the snowpack. This layer has been found on North, East and West aspects above and near treeline.  Its only absence is in southern facing locations where snow has melted off between storms and in areas where snow has been significantly stripped by wind.  The second and more variable is a set of persistent weak layers, facets, and near-surface facets, located above and below various melt-free crusts.  The continuity of these layers has been harder to assess, but if present continuously in the snowpack, these layers could also result in large avalanches.

Complicating the situation are the high winds that have arrived with the storm.  These have likely stripped some areas and loaded others.  In areas of additional loading, this could cause failure of the basal facets, making for large to very large avalanches with 3'-6' crowns.  Wind loading will also stress other persistent weak layers in the snowpack.

Yesterday, the near treeline and above treeline winds were shifting in nearly all directions.  Wind slab will be present today in potentially atypical areas, such as below treeline.  Travel slowly and cautiously and avoid wind drifted locations.  Retreat or find a different route if cracking or shearing is observed.  

Backcountry travel near and above treeline is not recommended.  Visibility will be limited by heavy snow, blowing snow, and clouds.  

Note that the snowpack depth and layers were quite variable pre-storm.   For those seeking more information, please view the observations page.  https://kachinapeaks.org/Observations/#/view/observations.   You can also check out the snowpits published this week at snowpilot.org.

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