Bollettino valanghe

Salt Lake

Pubblicato il Dec 26, 2021valido fino al Dec 27, 2021Utah Avalanche Center

Pericolo valanghe

Alta quota
Limite del bosco
Sotto il limite del bosco

Non aggiornato — questo bollettino è scaduto 5 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

The avalanche danger is HIGH on mid and upper elevation aspects facing west through north and east where strong winds and recent snowfall have created dangerous avalanche conditions. Both natural and human-triggered avalanches are likely. Travel in or below avalanche terrain is not recommended on west/north/east aspects at the mid and upper elevations.

There is a CONSIDERABLE avalanche danger on mid and upper elevation aspects facing southwest, south and southeast. Low elevations have a Moderate avalanche danger.

Problemi valanghivi

Persistent Slabs
N
NE
E
SE
S
SW
W
NW
Alta quota
Limite del bosco
Sotto il limite del bosco
Probabilità
Very Likely
Dimensione
4
Heavy snowfall and strong winds have overloaded a persistent weak layer (PWL) of faceted snow down near the ground on mid and upper elevation aspects facing west through north and east. This weak layer formed from snow that fell earlier this Autumn, and once we buried this weak layer beginning on December 9, the PWL has become reactive with avalanching on every loading event of new snow and/or wind.

Avalanches failing on this weak layer may be triggered remotely (from a distance) or from below. Any avalanche failing on this PWL may break down 2-6' deep (possibly deeper) and propagate hundreds of feet wide.

Do not travel on or below slopes approaching 30 degrees or steeper on mid and upper elevation aspects facing west through north and east.

The photo below shows the poor structure of strong snow over weak snow.
Wind Slabs
N
NE
E
SE
S
SW
W
NW
Alta quota
Limite del bosco
Sotto il limite del bosco
Probabilità
Likely
Dimensione
3
Strong winds have created dense wind drifts on all aspects at the mid and upper elevations. Although the winds have been from the west/southwest, winds this strong can channel snow around terrain features and create fresh drifts on all aspects, including well-down off of ridge lines. You may even find fresh wind drifts at unusually low elevations below 8,000'.

On mid and upper elevation slopes facing west through north and east, these drifts will overload the buried layer of weak faceted snow down near the ground.
Storm Slabs
N
NE
E
SE
S
SW
W
NW
Alta quota
Limite del bosco
Sotto il limite del bosco
Probabilità
Likely
Dimensione
2
New snow avalanches will be particularly sensitive during the morning hours during high snowfall rates. Natural avalanches may be possible in the steepest terrain...Avalanches may also be triggered at a distance during this time.

Avalanche Warning

THE AVALANCHE DANGER IS HIGH WITH DANGEROUS AVALANCHE CONDITIONS.

AN AVALANCHE WARNING HAS BEEN ISSUED FOR THE MOUNTAINS OF MUCH OF THE STATE OF UTAH, INCLUDING THE WASATCH RANGE...BEAR RIVER RANGE...UINTA MOUNTAINS...AND THE MANTI-SKYLINE.

HEAVY DENSE SNOWFALL AND STRONG WINDS HAVE CREATED DANGEROUS AVALANCHE CONDITIONS. BOTH HUMAN TRIGGERED AND NATURAL AVALANCHES ARE LIKELY. STAY OFF OF AND OUT FROM UNDER SLOPES STEEPER THAN 30 DEGREES.

Special Announcement

Avalanche conditions are very dangerous across most of the State of Utah as discussed by our staff in this video.

Help us help you: Take this quick quiz after you read the forecast. This will test what you've learned from today's forecast. You'll get feedback on what you learned and we'll find out how well we are conveying our message. You'll automatically be entered in a drawing for gear at the end of the season.

Recent Activity

Ski area avalanche teams found scattered and generally stubborn wind slabs yesterday. Piecemeal pockets of avalanches into the older snow layering continue to be triggered with explosives. Along the PC ridgeline, a snowcat operating at a ski area remotely triggered a sizeable avalanche into the October snow on a north facing slope at 9700'. Large collapses continue to be reported along the PC ridgeline.

In the backcountry, two new natural (possible) wind slabs released along the Cardiac Ridge at 10,400' and 10,600' NE facing while a natural cornice fall triggered a wind slab in Jaws of upper Days fork of BCC.

You can get caught up by reading our Week in Review where we summarize significant snow and weather events from this past week.

Snow and Weather

A cold front is rapidly approaching the Wasatch this morning and we'll see another good shot of snow with this system. Many areas will see 8-14" of new snow by the time it rolls east ahead of another, much colder storm for Monday.

It's currently snowing with 1-3" on the snow stakes already. Temperatures are in the upper teens and low 20s.

As my colleague Eric Trenbeath likes to say, though, The Story is the Wind.

South to southwesterly winds increased overnight with hourly averages of 30-40mph. Gusts have reached 65mph.

For today, look for heavy snowfall rates around 8-10am with 2"/hour expected. Winds will shift to the west with frontal passage but remain moderate/borderline strong. Temperatures will be in the low 20s.

We have another storm on tap for Monday that'll produce another round of snow. Temperatures crash to the low single digits with this storm. Another foot or more of snow is possible by Monday night.

General Announcements

Who's up for some free avalanche training? Get a refresher, become better prepared for an upcoming avalanche class, or just boost your skills. Go to https://learn.kbyg.org/ and scroll down to Step 2 for a series of interactive online avalanche courses produced by the UAC.

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