Bollettino valanghe

Northern Wallowas

Wallowa Avalanche Center
Vedi sulla mappa

Pericolo valanghe

Sun
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
Open full map
Non aggiornato — questo bollettino è scaduto 6 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

A deeper snowpack is often times a stronger snowpack.  With the deepest snowpack of all the forecast zones, the Southern Wallowas still host a complex array of layers within the pack.  New snow still available for transport by wind could form shallow windslabs that are sensitive to a person or machine.  If triggered in an area that holds a shallower snowpack, the deeper persistent weak layers could be impacted, creating a larger, more destructive avalanche.  Better stability exists below treeline, where there is less of a slab above older weak layers. 

Problemi valanghivi

  • Wind Slabs

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

    Look for freshly formed wind slab development along leeward ridgelines and cross loaded mid slope terrain features.  Hollow sounding and rounded pillows in these catchment zones are great ways to identify-and avoid terrain that is being loaded by the wind.  In areas that host a shallower snowpack, it will still be possible for a wind slab to step down into the older weaker snow deeper in the snowpack.  Observers on Wednesday indicated large natural avalanches that likely were triggered in this way.  

  • Deep Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–3

    The monster in the basement continues to sleep.  While it is becoming increasingly hard to trigger- a deep persistent slab is still possible.  It would be more likely to find a trigger point in steep rocky terrain that holds a shallower snowpack.  If these shallower areas are well connected to a deeper snowpack,  a large, deadly avalanche could easily propogate hundreds of yards.  Best to not try to thread the needle with this type of avalanche problem that can often lure a rider into steeper terrain with false stable test results.  Play the long game. 

    Check out Killians Extended Column Test from earlier in the week.  He finishes the 30 loading steps of the test with no result.  He follows up with a couple harder hits- and BAM- virtually the whole snowpack falls out of the pit.  A great example of seemingly stable results from a deep persistent slab problem.  

Avalanche Discussion

Great riding conditions continued to be found on lower angle slopes in wind sheltered terrain.   Venturing into the Southwest reaches of the Wallowas this week, I found a weak snowpack structure that exemplifies what we mean by shallower snowacks having worse stabilty.  See the snowpack structure differences in the pictures below.  

Regioni coperte