Boletín de aludes

Salt Lake

Publicado el Feb 6, 2025válido hasta el Feb 7, 2025Utah Avalanche Center

Peligro de aludes

Alta montaña
Límite del bosque
Bajo el límite del bosque

Desactualizado: este boletín caducó 2 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

A MODERATE avalanche danger exists on mostly northwest to north to east facing slopes for lingering wind slabs at the mid and upper elevations and for possible gouging wet avalanches down low. Cornices remain tender and are to be avoided. I'd also continue to avoid runout zones where glide avalanches release. (More below)

Problemas de aludes

Wind Slabs
N
NE
E
SE
S
SW
W
NW
Alta montaña
Límite del bosque
Bajo el límite del bosque
Probabilidad
Unlikely
Tamaño
2
The winds remain merciless. Hard and soft slabs of wind drifted snow litter the steep terrain, although they are more stubborn and sluggish than late weekend into Monday. I would chalk them up as stable, but many of these wind slabs, however, do rest upon a layer of weak snow (last week's snow surface) and remain prone to triggering. Long time avalanche professional Sean Zimmerman-Wall discusses the snowpack with an excellent report (with his Pro 2 class) in White Pine of LCC that is well worth reading.

It may be possible for any new wind slab to step down into weak faceted grains near the ground, particular in areas that avalanched previously this winter.

Cornices are becoming unruly along the ridgelines - remember to give these growing monsters a wide berth.
Persistent Slabs
N
NE
E
SE
S
SW
W
NW
Alta montaña
Límite del bosque
Bajo el límite del bosque
Probabilidad
Unlikely
Tamaño
3
There are two buried persistent weak layers (PWL) in the snowpack:

The upper layer formed during last week’s cold, clear weather and many wind slabs are failing at this layer.

The lower layer, near the ground, formed in December and has caused large avalanches, including two fatalities during the Holiday Avalanche Cycle. This layer is most likely to be triggered on steep, thin snowpack areas, rocky gullies, and repeater slopes (areas that have previously avalanched). Avalanches up to 1–4+ feet deep possible.
Loose Wet
N
NE
E
SE
S
SW
W
NW
Alta montaña
Límite del bosque
Bajo el límite del bosque
Probabilidad
Unlikely
Tamaño
2
The temperature graph is from the Mill D North weather station at 9000' and shows last night's dip in temperatures and subsequent rebound. I do think that this window of clearing skies and drop in temps will have reduced the likelihood of triggering wet avalanches, but the isothermal wet snow at the mid and low elevations has not had time to completely lock up. I could picture any avalanche from above still gouging down into unconsolidated grains. By tomorrow into the weekend, however, things should be locked up tight as a drum and it'll be nice to take wet avalanches off the menu in early February.

Special Announcement

The Preliminary Report for Monday's Monte Cristo avalanche fatality is HERE.

Our condolences go out to the victim's friends and family and all those affected by this tragic accident. UAC staff visited the site on Tuesday and a full report is forthcoming.

Recent Activity

It was fairly quiet in the backcountry yesterday. A natural cornice fall triggered a 1-2' deep and 150' wide soft slab along the PC ridgeline (Igloo Chutes area) on a steep east facing slope at 9200'. In mid-canyon of BCC, it looks as if a shallow wet slab peeled off the rocks in the Argenta Chutes and ran over a thousand feet down the path, leaving an impressive debris pile (B photo). The starting zone was north facing at roughly 8400'. With extensive control work, the Deer Valley avalanche teams triggered a monster of an avalanche that stepped to the ground near the Daly Bowl area.

Observations and Avalanches

Snow and Weather

Yesterday afternoon's frontal passage was as advertised: all theater and pyrotechnics; smoke and mirrors, a fireworks display. A carnival show.

But then you pull back the curtain and nothing is there.

In truth, most areas picked up an inch or two of graupel and temperatures mercifully dropped behind the cold front.

But now the term whiplash comes to mind: we have a storm on tap for tomorrow and - in-lockstep - temperatures have rebounded back into the mid to upper-20s and winds are again moderate to strong from the southwest. Skies have scattered clouds but I bet we'll see a few flurries by the afternoon. Tomorrow's storm will probably have an initial rain/snow line of up to 7500' (possibly as high as 8000') and it looks as if most of the precipitation will arrive warm and dense ahead of a suppertime cold front. 6-12" is a fair bet; maybe more, favoring upper Big Cottonwood and the south end of the PC ridgeline. Winds are to remain moderate to strong from the west-southwest for most the day. By evening, we'll see some light snow in the valley and mountain temps plummet to the low single digits by late weekend. The long term looks somewhat active.

Additional Info

Glide avalanches are notoriously unpredictable and not triggered by humans; they run naturally and catastrophically. More info on glide avalanches.

I suspect that Stairs Gulch, Broads Fork, and Mill B South of lower BCC as well as upper Porter Fork are a war zone of debris from glide avalanches from the warm spell. I'd still avoid runout zones in these areas over the next day or two.

General Announcements

CLICK HERE FOR MORE GENERAL INFO AND FAQ

This information does not apply to developed ski areas or highways where avalanche control is normally done. This forecast is from the U.S.D.A. Forest Service, which is solely responsible for its content. This forecast describes general avalanche conditions and local variations always occur.

Observations and Avalanches

Backcountry Emergency Procedures