Boletín de aludes

Provo

Publicado el Feb 11, 2021válido hasta el Feb 12, 2021Utah Avalanche Center

Peligro de aludes

Alta montaña
Límite del bosque
Bajo el límite del bosque

Desactualizado: este boletín caducó 6 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

The avalanche danger is CONSIDERABLE on steep slopes facing west through north through southeast at the upper elevations. The danger is also CONSIDERABLE on mid-elevation steep terrain that faces northwest through east. Recent snowfall and strong winds have overloaded the snowpack on many slopes at the mid and upper elevations. Dangerous avalanche conditions exist. Any natural or human-triggered avalanche can be up to 5' deep, several-hundred feet wide, and likely unsurvivable. The remaining mid and upper elevation aspects have a MODERATE avalanche danger. Below 8,000', there is a LOW danger.

Problemas de aludes

Persistent Slabs
N
NE
E
SE
S
SW
W
NW
Alta montaña
Límite del bosque
Bajo el límite del bosque
Probabilidad
Likely
Tamaño
4
Dangerous avalanches 2-5' deep and hundreds of feet wide are still possible on steep mid and upper elevation slopes. These conditions will be most pronounced on steep northwest to southeast facing slopes. If an area has any signs of wind loading, we could see even deeper avalanches breaking, up to 5-10' deep, that initially fail in the wind drifted snow and step down into the weak faceted snow near the ground. Either way, these avalanches are likely to be unsurvivable.

A few words of caution:

Signs of instability may not be present: you may or may not see or experience shooting cracks or audible whumping.

Tracks on the slope offer zero signs of stability. Avalanches will take out multiple existing tracks.

You can trigger these avalanches from a distance or below.

Any fresh wind slab or new snow avalanche may step down into this older layering of weak snow.

Bottom Line: There is no outsmarting this problem - avoidance is the answer. If you're heading out into the backcountry today, be sure to stick to terrain that's under 30° degrees in slope steepness with nothing steep above or adjacent to you. Dangerous avalanche conditions exist, and human triggered avalanches are likely.

Particularly dangerous areas would include Snake Creek, upper American Fork, upper Mill Creek, and much of the Park City ridgeline.
Wind Slabs
N
NE
E
SE
S
SW
W
NW
Alta montaña
Límite del bosque
Bajo el límite del bosque
Probabilidad
Possible
Tamaño
2
The winds have been relentless over the past few days, mainly blowing from a westerly direction. Days of sustained high winds can deposit snow around terrain features on almost any aspect, called cross-loading. For this reason, I would expect to find stubborn slabs of wind drifted snow at all upper and mid-elevation slopes, especially along with terrain features such as ridgelines, sub ridges, and gullies.

Approach each new drift with caution; cracking and collapsing may not be evident today. Look for any slopes with signs of wind drifted snow and avoiding those slopes.

Pay attention to cornices: Many ridgelines now have growing cornices. We have seen a few cornice-triggered avalanches now. Be sure to give cornices a wide berth as they typically break much further back than expected and could trigger a much larger avalanche below if they fail.

Special Announcement

We are filled with grief to report four avalanche fatalities that occurred Saturday in the Wilson Glade of upper Mill Creek Canyon. The avalanche involved two separate parties. Our deepest condolences go out to the friends and families involved. Our deepest gratitude goes out to Wasatch Backcountry Rescue, Intermountain Lifeflight, the Department of Public Safety, the United States Forest Service, and Brighton, Solitude and Alta Ski Patrols for providing resources and support during this tragic accident. We investigated the accident Sunday; our preliminary report has been published. Please be patient and know the UAC staff is working around the clock to get the final report done.

Recent Activity

Yesterday, there were no new avalanches reported from the backcountry. However, we did get two reports of some older avalanche activity from the weekend's natural and human triggered cycle. One avalanche was from Mineral Fork, roughly 1,000' wide, 2-3' feet deep, and running full track to the creek ~ 1,200' vertical. The second slide was from the Bountiful Sessions with about the same dimensions. Be sure to catch up on all the observations HERE.

Snow and Weather

The National Weather Service (NWS) has issued a Winter Storm Warning in effect from 08:00 pm tonight through Friday 11:00 pm. For today, we should see increasing clouds with some snow showers possible; however, any accumulations will only be a trace to a couple of inches. Mountain temperatures will climb into the upper 20's to low 30's at 8500'. Snow will begin to fill into the area this evening around 08:00 pm. Westerly winds are forecasted to increase later this afternoon and into the evening, with the strongest winds overnight.

The winds are currently blowing from the westerly direction at 10-15 mph gusting into 20's mph. The free air winds are moving much faster from the west and are blowing at speeds of 25-30 mph, gusting into the 40's mph. Mountain temperatures are in the upper teens °F above about 9,000'.

Buckle your seatbelts as we have a very active storm cycle forecasted. The first storm will be tonight into Friday, and I am seeing 6-12" (0.5"-1.0" swe) of snow by Friday evening. The next storm will be Saturday evening, lasting into Sunday with perhaps 12-16" of snow with another inch of water. Then the best looking storm is slated for Monday into Tuesday into Wednesday. By the end of the cycle on Thursday, we could see up to 3"-4" of snow water equivalent and possibly 50"-70" of snow.

Now the caveat; it's easy to get excited, but the truth is, the details on these storms are still a long way out, and we should sip the weather kool-aide instead of chugging it. I am a little skeptical that this will all shake out. But hey, it's going to snow. Stay tuned, and we will do our best to keep up to date with changing weather.

General Announcements

Please visit this website with information about Responsible Winter Recreation by the Utah Office of Outdoor Recreation.

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