Bollettino valanghe

Salt Lake

Pubblicato il Feb 21, 2021valido fino al Feb 22, 2021Utah Avalanche Center

Pericolo valanghe

Alta quota
Limite del bosco
Sotto il limite del bosco

Non aggiornato — questo bollettino è scaduto 6 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Areas of CONSIDERABLE avalanche danger exist on many slopes of the mid and upper elevations. Considerable means that dangerous human triggered avalanches are likely. The danger is more prevalent on west to north to southeast facing slopes and on any recently wind drifted terrain. Cornices are to be avoided.

All the experienced backcountry riders I know are setting wide margins of safety and continue to rule out steep terrain for now.

The Good News: Safe and enjoyable powder can be found on low angle slopes with no overhead hazard.

Problemi valanghivi

Wind Slabs
N
NE
E
SE
S
SW
W
NW
Alta quota
Limite del bosco
Sotto il limite del bosco
Probabilità
Possible
Dimensione
2
Lingering wind drifts and cornices may still be sensitive to provocation today and will be more prevalent in the upper elevations or just to the lee of some of the more exposed mid-elevation ridgelines. A triggered wind slab or cornice may or may not step down into deeper weak layers. Shooting cracks can be good indicators of wind slab development.

Minor sluffing in the new snow can be expected in the steepest terrain.
Persistent Slabs
N
NE
E
SE
S
SW
W
NW
Alta quota
Limite del bosco
Sotto il limite del bosco
Probabilità
Likely
Dimensione
4
I anticipate that a few people will begin stepping out into steeper terrain today but the difference between joy and terror is sometimes just a matter of a few degrees of separation. As in about 10° of separation. You can find just as much joy on low angle terrain as you can on steep high angle terrain today. The options are simple.

Low Risk - High Reward

High Risk - High Reward

I will say that this takes discipline to stay the course and not drift into steeper terrain, even if you see tracks on those slopes. With this type of tricky snow structure, tracks offer zero indication of stability. Similarly, you may not experience any cracking or collapsing. No matter - patience is required. You are still likely to trigger a deeper slab avalanche 2-5' deep where the slab is thinner, in steep rocky terrain, or in areas that have avalanched previously this winter. While it may be possible to find this layering anywhere in the Wasatch, I am most suspect of terrain along the periphery of the Cottonwoods such as Mill Creek, the PC ridgeline, Lambs/Mt Aire, Snake Creek, and the transitional zone toward the Bountiful/Sessions.

Do the Work-

Ski cuts and cornice drops can be dangerous and dangerously misleading indicators of stability

Dig down and if you see weak facets in the snowpack, avoid steep terrain (see Trent's video below from Broad's Fork yesterday)

Choose a completely safe uptrack. You are often more vulnerable while ascending.

Expose only one person at a time and keep tabs on people all the time

Special Announcement

On Monday, February 22, at 7 PM, the UAC will livestream a one hour review and debrief of the tragic Wilson Glades avalanche accident, followed by a Q & A period. The link for registration is HERE.

A good primer for this will be to listen in to Friday's RadioWest conversation about avalanches and the incident. Stream it here or wherever you get your favorite podcasts.

Recent Activity

Dangerous avalanche conditions consume the West: The backcountry community has suffered 22 avalanche fatalities in 22 days, the most recent from Idaho and Wyoming. INFO. Utah is up to 6 avalanche fatalities for the season.

Ski area control teams and backcountry travelers along the higher alpine ridgelines noted both sensitive cornices and sensitive but shallow wind drifts yesterday. We did not hear of any avalanches breaking into deeper layers.

Snow and Weather

We'll squeeze the last bits of water from a stone this morning from an under-producing storm. But one can't complain.

Most areas picked up another 2-4" of 6% overnight, with total snowfall in the 4-7" range. Mountain temperatures have plummeted with the passing wave and are in the single digits. West to northwest winds remain a player, blowing 35-45mph with gusts to 65, although these sustained wind speeds seem confined to the highest peaks and ridgelines. 10k anemometers spin 15-20mph with gusts to 30.

Skies will trend partly cloudy this afternoon with mountain temps in the teens up high, the low 20s down low. Temps trend warmer tomorrow.

It finally feels like we have a real winter under our feet. Riding conditions are excellent and coverage is pushing 80-120" in the higher reaches of the Cottonwoods and 50-70" along the PC ridgeline. The past week has been a blur. Read more about it in Greg Gagne's patented Week in Review.

Approximate snow and water totals over the past 10 days:

Little Cottonwood: 5-7' (4-6.75" water)

Big Cottonwood: 2-5' (2-5" water)

PC Ridgeline: 2-3' (1-2.5" water)

Ogden area: 2-3' (1-2.5" water)

Provo area: 1-2.5' (1-2.5" water)

pc: Ashley Patterson, Happiness

Additional Info

These are two examples of avalanches from the recent avalanche cycle: the first is off Tuscarora in the Brighton periphery. The second is near West Scotties in the lower White Pine drainage of LCC. The first is upper elevation, east facing and open terrain. The second is mid-elevation, west facing, and more interspersed with trees. Quite different from one another, but they are both avalanche terrain. Both could kill you. Slope angle is the great equalizer right now.

pc: Bill Nalli

pc: Mitch Potter

General Announcements

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

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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