Bollettino valanghe

San Francisco Peaks / Kachina Peaks Wilderness

Kachina Peaks Avalanche Center
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Pericolo valanghe

Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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In sintesi

A skier or rider could trigger a wind slab avalanche today in isolated pockets of terrain, especially on steep slopes.  Moderate winds continued yesterday out of the NNW  and West.  Avoid pockets of wind deposited snow in and around terrain features such as ridgelines and rock outcrops--these will be the most likely locations to find reactive wind slabs.  These avalanches will probably be small in size but could knock a skier or rider from their feet and into consequential terrain--continue to watch for signs of instability, such as cracking and shearing, and use appropriate travel techniques.

A big thank you to everyone who supported Mikee Linville Fundraiser!  Thank you for making this event a great success and for supporting avalanche education in Northern Arizona!

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    Yesterday, moderate winds out of the west and north-northwest at NTL and ATL continued to move snow around the San Francisco Peaks.  Already established wind slabs may have accumulated newer and more reactive snow.  Skiers and riders should watch for wind slab presence in specific terrain features such as the leeward side of ridgelines, in avalanche path starting zones, in crossloaded gullies, chutes, and on steep convex rollovers.  Wind slab avalanches will be more sensitive in steep terrain.  A wind slab avalanche could be encountered on any aspect due to microterrain features and multiple wind directions occurring in the last 24 hours.

    Today, light winds with moderate gusts are forecast for the region.  Winds could shift back to the west as early as this morning.  Many west and southwest facing slopes are stripped up high and have anti-tracks in wide open slopes near treeline.  Don't let these observations lull you into a sense of overconfidence.  Continue to be on the lookout for cracking and use assessments on upper terrain to gain a sense of the potential reactivity of these slabs.  Wind slab avalanches will likely be small today with crowns of 4-8" and may partially bury a skier or rider, or cause a fall over rocks or other steep terrain.

    Thus far the new snow seems to be bonding well with the old snow bed surface.  However, this may not be the case everywhere on the mountain.  Continue to look for signs of ideal bed surface such as sliding out of the skin track or new snow shearing away from the old snow surface.  These are signs that wind slabs could be more reactive and occur over a larger area.  Using appropriate travel techniques, such as keeping eyes on one another and moving cautiously when encountering new aspects and microterrain features, will be important today.  

     

Avalanche Discussion

Snow totals from Friday's fast moving storm are 6" of new snow at the Snowslide Canyon SNOTEL site and 9" of snow at the Snowbowl 10,800 ft. survey stake.  Winds of all directions have affected the mountain since this snow fell.  Wind slabs have likely stiffened with cold temperatures and may not be as reactive as yesterday, but continue to be on the look out for signs of instability and use caution when moving onto new aspects and terrain features.

Be cautious of loaded started zones following this wind and snow event.  Some locations may be heavily loaded and, although unlikely, if these locations release they could result in a larger than predicted avalanche of up to D2 in size.  

Much of the Inner Basin has not had observations in the last 24 hours. As always, use your own observations to wisely inform your decision-making, especially if your travel plans today include north—and east-facing slopes. Search for signs of instability and use conservative travel strategies.  

The pre-storm bed surface may be a factor in the sensitivity of these newly formed wind slabs.  Prior to the storm much of the near treeline and above treeline terrain was either a hardened melt-freeze crust or wind board of 4 Finger to 1 Finger hardness.  This new snow may not bond well with the old surface.  If you're sliding out of your skin track and having trouble gaining traction, this is a sign that wind slabs may be more sensitive and likely to slide on the old snow surface.

Currently, the SNOTEL site in Snowslide Canyon is nearly 150% of the median snow water equivalent for this time of year. Snow depths in the inner basin near treeline are averaging around 200 cm.  This year, spring powder keeps the snowpack deep at higher elevations, and with this bonus comes increased avalanche danger. Keep a watchful eye, and don't let the last couple of days of spring-like weather lull you into a false sense of security.  

Recent snowpits can be found at https://snowpilot.org/snowpits/query?field_loaction_tid=4.

Recent observations can be found here.

Once again, thank you for supporting the Mikee Linville Fundraiser on the Agassiz deck yesterday!  All proceeds from this event support our avalanche education scholarships.  It's not too late to be involved, check out the Kachina Peaks Avalanche Center website for our ongoing Power Pass and R&D Splitboard bding raffle!

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