Bollettino valanghe

San Francisco Peaks / Kachina Peaks Wilderness

Kachina Peaks Avalanche Center
Vedi sulla mappa

Pericolo valanghe

Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
Open full map
Non aggiornato — questo bollettino è scaduto 2 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Triggering a wind slab avalanche will be possible today.  Winds ranging from the south, west and north combined with new snow have created specific and possibly widespread locations of wind driven deposition.  Avoid the leeward side of ridgelines, cross loaded gullies, avalanche path starting zones, and pillowed terrain features.  These avalanches could be large enough to bury a skier or rider.  Watch for signs of instability, such as cracking and whumping, and have an appropriate egress planned if these occur.

Today's the big day!  Whatever the weather, join us on the Agassiz Lodge deck for the Mikee Linville Fundraiser. This event is the primary fundraiser for the avalanche education scholarship fund.  Help make avalanche education affordable!   Your support makes this happen! 

Problemi valanghivi

  • Wind Slabs

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

    Yesterday, southwest winds were strong, with gusts in the extreme category.  In the evening, winds dropped to moderate, making for ideal conditions for wind slab formation.  Complicating the situation is that winds have ranged from the south to west to north in the past 24 hours.  Skiers and riders should watch for wind slab presence in specific and possibly widespread terrain features such as the leeward side of ridgelines, in avalanche path starting zones, in crossloaded gullies and chutes, and on rollovers.  Wind slab avalanches will be more sensitive in steep terrain features.  Although the dominant winds were from the south and southwest, a wind slab avalanche could be encountered on all aspects due to shifting winds and high wind velocities that tend to be redirected by smaller terrain features.  For those looking to get out, today will be an excellent day to play it safe and stick to sheltered below treeline terrain.  

    Today, moderate winds and strong gusts are forecast for the region.  On upper ridgelines, snow may be stripped by upslope and southwest winds, but in specific locations, drifted snow will continue to load, making for possibly large (D2) avalanches of 8-20" crown height.  Upon entering the backcountry be conservative and observant; look for wind loading and test the reactivity of slopes by traveling a couple feet above existing skin tracks, conducting hand pits, and performing switchback assessments.  Look to the ridgelines for the direction of spindrift and active loading.  Finally, watch for cracking and shearing, and if slabs release with any cohesion, don't be afraid to back off and choose lower angle terrain.  

    The incoming snow and current wind transportation may be loading pre-storm slopes that were slick melt-freeze crust and hardened wind board.  It is possible that these surfaces may make for ideal bed surfaces and increase the sensitivity and likelihood of wind slab and storm slab avalanches.  Depending on the temperatures and associated timing, some of these slabs could be quite reactive to the weight of a skier or rider.  Play it safe today and retreat if you see obvious signs of instability, such as shooting cracks, or if you get reactivity in any stability assessments.  Hard snow over soft snow is a sign that slopes could release.  Proceed cautiously, have a tour plan, spread out on the approach, and ski one at a time.

     

     

Avalanche Discussion

Snow totals from the Snowslide Canyon SNOTEL site at 9,700 ft. are 6" of snow and just .2" of SWE.  Snowbowl is reporting 9" of snow at the 10,800 ft. survey stake.  This new snow, in combination with winds that ranged from south to west to north, could make for reactive wind slab today.  Winds yesterday were strong to extreme but these shifted direction northerly and dropped to moderate throughout the night.  Wind slabs could be widespread throughout the mountain, and the sensitivity could vary significantly based on aspect.  Be cautious today and constantly on the look out for shooting cracks and changes in windslab reactivity.  Wind slabs may be present in unexpected areas, and the cross-loading effect could make some pockets more reactive than one might expect.  This could lead to larger wind slab releases similar to those experienced last weekend.

The storm started producing earlier than expected yesterday, with skies starting off clear, turning cloudy quickly, and then releasing snow as early as 11:00 AM.  Accumulation in the afternoon came in with strong to extreme winds.  Today, the winds are forecast to blow from the west,  but the weather station at 11,500' has been showing a more northern direction.  Conditions in the backcountry could be tolerable this afternoon as clouds clear.  If you're venturing into this terrain, be very observant for wind slab formation and avoid locations of wind drifts, pockets of mounded snow, and cross loaded snow in gullies.

This storm system started with warming temperatures that continued to drop as the storm and evening went on.  Most of this snow came in right side up, but the wind has had its way with it, so be observant for any signs of instability and don't let below treeline observations create a false representation of what's present in higher less protected elevation zones.

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. 

Come join Kachina Peaks Avalanche Center today 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.  Many thanks to everyone who made our avalanche courses a success this season, and a big thank you to all our participants! KPAC is especially grateful to our generous community. Your support makes avalanche forecasting and education possible in Northern Arizona. 100% of KPAC's funding comes from fundraisers, donations, and grants - your contribution matters!

Regioni coperte