Bollettino valanghe

Galena Summit & Eastern Mtns

Sawtooth Avalanche Center
Vedi sulla mappa

Pericolo valanghe

Sun
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
Open full map
Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

You're most likely to trigger avalanches on slopes where the wind has formed drifts or stiffened the snow surface. Large avalanches could also occur in steep wind-sheltered terrain. Avalanches may be triggered remotely—from gentler terrain above, below, and to the sides of steep slopes. Smaller loose snow avalanches are likely this afternoon on steep slopes that face the sun. 

Problemi valanghivi

  • Persistent Slabs

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

    Triggering a 2-3' thick persistent slab avalanche is possible on steep slopes. Persistent weak layers (sugary facets, surface hoar, or crusts) exist on most aspects and elevations. The widespread nature of this problem is unusual. You could trigger a large, dangerous avalanche on a variety of slopes including lower elevations and in terrain sheltered from the wind.

    Wind and snow over the past few days created fresh wind slabs (see below). The added weight is stressing the buried weak layers, especially at middle and upper elevations where thicker, heavy wind drifts are more common. Yesterday near Red Fish Lake, JP experienced collapsing each time he stepped off of the skin track. This "red flag" warning sign of instability is becoming much less common. This a sign that the snowpack is slowly stabilizing but we're not out of the woods yet. Remember that you could trigger slides remotely—from gentler terrain above, below, and to the sides of steep slopes. These avalanches may break wider than expected or higher on the slope above you. 

    Unfortunately, avoiding slopes steep enough to slide is the only way to effectively manage this problem. I'll be sticking to lower-angled, wind-sheltered slopes to reduce my risk.

    (12/13/2022) Very large avalanche on a W and SW face at 10,400' at the head of Murdock Ck NE of Ketchum.

  • Wind Slabs

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

    Snow and wind over the last few days built sensitive slabs on many slopes (video). These slabs will be thicker and more widespread at middle and upper elevations but the extreme wind event also formed slabs at low elevations right down to the valley bottom. Fresh drifts sit atop a weak surface of crusts, facets, and surface hoar (photo). 

    On Wednesday, Skiers triggered wind slab avalanches in Indian Ck and Quigley Canyon, and dozens of natural wind slab avalanches released on a variety of aspects at middle and low elevations from the foothills north of Fairfield to the mountains around Hailey. In the Soldiers, a very large natural avalanche released on a heavily wind-loaded upper elevation slope. The dense hard slab was heavy enough to "step down" to weak snow near the ground (report). In the Boulders, a set of impressive wind slab avalanches released in Eagle Ck (above/right), cascading nearly 2,000 vertical feet before piling debris in the gully below. 

    Today, you should steer clear of obviously wind-loaded terrain. Unusually strong wind built slabs in unusual places. You may find them far below ridgelines, on the sides of gullies, and near prominent terrain features in normally sheltered areas. I'd assume any drift you encounter will be touchy to your weight until proven otherwise. Smaller wind slab avalanches could "step down", triggering the large persistent slab avalanches described above.

    Enjoy your Holiday weekend and be sure to check out the latest installment of our Weekend Update!

    (12/21/2022) A set of impressive wind slab avalanches on the headwall of Eagle Ck N. of Ketchum. SW and S @ 10,000'.

Avalanche Discussion

When writing the forecast in the morning I find it useful to imagine what I'd tell a friend visiting from out of town. And maybe that's you. If it is, props for finding the forecast. Here are the nuts and bolts of what I'd want them (you) to know:

  • Weak snow exists near the ground on most slopes. While the odds of triggering a very large avalanche involving this layer have generally decreased over the last week, this problem still dictates the type of terrain I'm willing to expose myself to. I'm still avoiding steep, consequential terrain particularly W-N-E facing slopes where the combination of weak snow and a thicker slab keep me feeling uneasy. 
  • An extreme wind event on the Solstice largely reshaped the snowpack. It formed slabs on many middle and upper elevation slopes but they also exist on isolated slopes down to the valley bottom. If one were to be triggered today, I'd expect it to be a hard slab that fails on some mix of facets or surface hoar and a crust or ice lens that survived the wind prior to burial. 
  • Uncertainty. In my 10+ years of forecasting, I can't recall a time that I've faced such an odd combination of snow and weather patterns. A widespread weak layer, an extreme wind event, and an Arctic cold front that's followed promptly by a sunny day in the mid-30s F. What will warming, tonight's rain, and tomorrow's temperature in the 40s F bring? That is a great question. Despite having no clear answer, I find solace in a simple rule—as my uncertainty in the conditions increases my appetite for complex or consequential terrain decreases.  

My advice is to remain conservative. The likelihood of a large avalanche is decreasing but the consequences if caught in a slide are not. Personally, that's a game I'm not willing to play. There are enough places to get in trouble out there today, that I'd feel more comfortable sticking to lower-angled slopes, or simple terrain that's disconnected from larger slopes. With that general baseline, I'd steer clear of obvious recently wind-loaded terrain. Not only is wind-sheltered terrain safer today, but the skiing and riding will almost certainly be more enjoyable. 

Regioni coperte