Avalanche forecast

San Francisco Peaks / Kachina Peaks Wilderness

Kachina Peaks Avalanche Center
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Avalanche danger

Mon
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

The avalanche danger remains MODERATE at and above treeline. Recent winds have formed and may further develop sensitive slabs. Collapsing has recently been encountered by multiple backcountry parties. With 1-2' of accumulation over the past 72 hours and recent winds, it will be possible to trigger a wind slab up to a foot deep. Carefully evaluate surface conditions at mid and upper elevations, especially below loaded ridgelines, convex rolls, and steeper loaded gulleys. Slopes with wind-loaded pillows, wind textures, and stiff or hollow-feeling snow should be considered suspect. 

Avalanche problems

  • Wind Slabs

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

    After 72 hours of unsettled weather, snow accumulation and shifting winds, we are within a prime period for encountering reactivity from potentially sensitive wind slabs.  Winds have shifted on the compass from south to northeast overnight, up to 24 mph, and are expected to increase speed in the morning hours. These northeast winds may have transported snow onto west and southwest aspects, particularly entrances to gulleys and near or below ridgelines The previous stiff, supportable and stubborn upper snowpack that we've been encountering the past few weeks on northerly aspects, has created the foundation as a potential bed surface for the recent wind and snow accumulation to form a cohesive slab upon.

    Multiple backcountry users  have recorded both artificial and intentional avalanches primarily on northerly aspects, up to 1' deep and consisting of fairly soft snow that could injure, bury or kill a backcountry user. Loaded convexities, entrances to gulleys,  and leeward slopes are key locations for slab development and hotspots for triggering an avalanche. To identify areas with wind slabs keep an eye out for stiff or hollow feeling snow in wind exposed areas and terrain. Utilize small test slopes to check for shooting cracks and determine how reactive wind slabs are to the weight of a skier or rider. Ensure you avoid the temptation to keep pushing into higher, steeper terrain, as wind slabs may be lurking beneath soft, low-density surface snow. 

    (3/15/2024)

    Soft slab avalanche triggered in the Humphreys Cirque on a north aspect.  This photo only shows half the crown. It propagated over to the rock near the orange arrow.  The crown was 8"-20" running on a 1 finger slab bed surface. 

    Photo: Paul Dawson

  • Persistent Slabs

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

    As the recent snow accumulation over the past 72 hours is still in the process of bonding to the weaker, older interface,  we must also recognize what may be lurking beneath. Throughout the season, our persistent weak layers have been found ranging from radiation formed facets above melt-freeze crusts, 1' down from the surface and recently, as deep as over 3' in snow profiles. Facet layers are notable for forming above solar crusts and have been observed in specific areas on both northerly and the edges of southerly. These solar crusts are facet factories when insulated deeper in the snowpack and typically time will either help bond snow to the crusts or create a larger, more developed facet weak layer. Basal facets, or depth hoar, has been of primary concern , as a skier or rider could trigger a layer to fail in shallow depths, which could propagate into a deeper drainage, gulley or connected slope. 

    The sensitivity of these facets has primarily been stubborn to reactive in snowpack assessments, but a trend of the depth hoar and basal persistent problem has been unreactive, giving space and focus to midpack reactivity as our layer of concern for the time being. Recent snowpack tests are showing reactivity on specific northerly aspects, 1-2' below the surface in large column tests. Though these layers have been dormant and have not been observed to cause an avalanche for quite some time, the likelihood is still possible and the consequences may be rising with each snowfall, waiting to tip the scales. 

    (3/14/2024) Facet development, found mid snowpack on southerly aspects above multiple melt-freeze crusts.   Photo: Eric R./ JP

Avalanche Discussion

Storm totals so far are 23" reported from Arizona Snowbowl  and 18" at the Snowslide Canyon SNOTEL.  Just over 2" of SWE has been recorded at the Snowslide Canyon  SNOTEL site since Thursday. 48 hours ago our forecaster team triggered two small soft slab D1 avalanches both on north aspects. 

The most common areas to find reactive wind slabs will be in steep terrain just below ridgelines, convex rolls, and in gullies. Be skeptical of slopes with relatively stiffer snow sitting on top of a softer layer. These fresh wind slabs don’t necessarily need to be very stiff to make avalanches as any snow that has been drifted into a deeper slab will be suspect and harder to assess. Warning signs like shooting cracks and collapsing, which have been evident within the last 24 hours, are clear indicators of unstable snow. Cracking is unsolicited evidence to see how well fractures are occuring, typically in the upper surface of the snowpack. Travel tests can be a very effective way to assess how sensitive theses surface problems are. This includes things like quick hand pits to see how easily the new snow is shearing off the surface, and traversing the top of short but steep test slopes to see if you can make a mini avalanche happen. Your best bet for staying out of trouble  and finding the best surface conditions to ski or ride,  is to look for slopes that are protected from the wind today. Yesterday, shooting cracks were generally localized on both lightly wind loaded and previously low density, wind stiffened surfaces . Collapsing, found primarily on northeast to northwest aspects, was felt and heard for under 2 seconds, which tells a tale that one cannot see on the surface between the bonding of new and old snow. Snowpack assessments, safe travel techniques on negotiable terrain and maintaining a high index of suspicion is best practice going forward, which cannot be emphasized enough.

As stated previously, beneath the surface there is an ever-changing and evolving persistent problem that is specific to our northerly terrain. Though we haven't observed undeniable activity in quite some time, maintaining appropriate travel decisions and making conservative choices in consequential terrain will ensure the best possible safety for you and your partners. This persistent problem has the potential to be 1-2' below the surface and will continue to stay through the end of the season though it is unlikely to be naturally triggered at this time. 

Many areas of our forecasting zone were previously stripped or shallow with rock, talus and vegetation exposed on the surface. With the recent accumulation of soft snow, areas that have been sheltered from the wind or nearby may be harboring hazards that deceive the unaware traveler. Maintain caution and feel beneath the surface often, at multiple aspects, to avoid an injury from being caught off guard or thrown off balance in simple to challenging terrain. We have limited information on backcountry conditions over the past 48 hours and due to limited visibility, observing natural avalanches in the full extent of our forecasting area has not been possible.  Create a plan with decision points, utilize safe traveling techniques and avoid having a runout zone above you as the skin track and slopes become more crowded over the next few days.

Come join Kachina Peaks Avalanche Center on Saturday, April 6th, at the Agassiz Lodge deck for the Mikee Linville Fundraiser!  All proceeds from this event go to our scholarship fund, which, to date, has resulted in over 29K of scholarship benefits!  For more information on how to get involved, visit kachinapeaks.org.  Much thanks to everyone who made our avalanche courses a success this season and a big thank you to all our participants!

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