Boletín de aludes

Salt Lake

Publicado el Dec 17, 2022válido hasta el Dec 18, 2022Utah Avalanche Center

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Peligro de aludes

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Desactualizado: este boletín caducó 4 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Tricky and dangerous avalanche conditions exist.

The avalanche danger is CONSIDERABLE on all northwest through east facing aspects at ALL ELEVATIONS (even LOW ELEVATIONS) for triggering avalanches 1-4' deep and hundreds of feet wide. These avalanches may be triggered at a distance, even from below. Areas of MODERATE avalanche danger exist on all other aspects and elevations. You can also trigger new soft slab avalanches of wind blown snow in the upper elevations today.

It's too risky: we do not recommend traveling on, below, or adjacent to slopes 30 degrees or steeper on northwest through north thorough the easterly aspects. Fortunately, safer and excellent riding can be found on low angle slopes with nothing steeper above you.

There were three serious avalanche accidents involving significant injuries this past week. I am fearful our luck has run out.

Problemas de aludes

Persistent Slabs
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NE
E
SE
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SW
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NW
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Probabilidad
Likely
Tamaño
3
There is weak, sugary faceted snow (a persistent weak layer, or PWL) on almost all aspects and elevations throughout the Wasatch Range. This PWL has been buried by several feet of storm snow and wind-drifted snow which has created dangerous avalanche conditions, with three serious avalanche accidents this past week. WHAT IS UNUSUAL is that each of these avalanche accidents took place in the lower elevations bands below 8000’. What this means is that these avalanches can occur not far from parking lots or trailheads.This PWL is especially dangerous on aspects facing northwest through north and east where triggering avalanches is likely.

There were other avalanches this past week that occurred at low elevations below 8,000, including Lambs Canyon, Daly Canyon, and Summit Park.

Although avalanches involving this PWL are less likely on solar aspects facing west through south, there is too much uncertainty given the amount of snow we have received this past week and avalanches failing in this PWL are still possible.

Fortunately, there is fantastic riding and travel conditions on low-angled slopes less than 30 degrees in steepness.

TREND: Steady
Wind Slabs
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NE
E
SE
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SW
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NW
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Probabilidad
Possible
Tamaño
2
Northwest winds overnight have had plenty of low-density snow to blow around and you are likely to find sensitive slabs of wind-drifted snow at the upper elevations. The new soft slabs will be most pronounced on north through east through south facing slopes. The avalanche in Snake Creek on Thursday likely failed due to recent wind loading and there were other reports of sensitive wind drifts from Thursday.

Any wind slab avalanche that you trigger has the potential to step down into deeper weak layers in the snowpack, creating a very large and dangerous avalanche.

Look for evidence of fresh drifts and wind slabs that look wavy, rounded, smooth, and pillowy, and avoid those slopes. Signs of sensitive wind-drifted snow include cracking and collapsing of the more dense drift over lower density snow below.

Long running dry sluffs are still possible in the cold, dry snow...and may transition to wet loose sluffs with today's direct sun and warming temperatures.

TREND: Decreasing danger

Special Avalanche Bulletin

DANGEROUS AND UNUSUAL AVALANCHE CONDITIONS WILL LAST THROUGH AT LEAST THIS WEEKEND. HEAVY SNOWFALL THIS PAST WEEK HAS CREATED DANGEROUS AVALANCHE CONDITIONS AT ALL ELEVATIONS. DON'T BE LURED BY THE BEAUTIFUL SUNNY SKIES AND FRESH POWDER INTO THINKING AVALANCHE CONDITIONS ARE SAFE WHEN THEY ARE NOT.

DO NOT TRAVEL ON, UNDERNEATH, OR ADJACENT TO SLOPES 30 DEGREES OR STEEPER ON SLOPES FACING NORTHWEST, NORTH, NORTHEAST, AND EAST WHERE TRIGGERING LARGE AND DANGEROUS AVALANCHES IS LIKELY. THIS INCLUDES LOW-ELEVATION FOOTHILLS WHERE AVALANCHES CAN OCCUR NOT FAR FROM PARKING AREAS AND TRAILHEADS.

Special Announcement

Park City Mountain Resort is planning on opening the Jupiter Lift area this weekend. Please avoid the Scott's and Pinecone areas for the rest of the season.

Recent Activity

Drew has published a blog "Dangerous and Unusual Avalanche Conditions" describing the avalanche activity over this past week.

THERE WERE THREE SIGNIFICANT AVALANCHE ACCIDENTS THIS WEEK with serious injuries. Two injured parties required rescues. The avalanches broke down over 2' deep into the layer of November facets. These avalanches occurred at low elevations below 8,000':

Tuesday - Pink Pine Ridge 7,800' North-facing 2-3' deep, 60' wide. Read the preliminary report. UAC staff visited the area on Wednesday, but due to avalanche danger, chose not to approach the actual avalanche:

Wednesday- Thomas Fork in Neffs Canyon 7,200' North-facing 2' deep 200' wide. Read the preliminary report.

Friday, December 9, an avalanche accident on Santaquin Peak in the Provo mountains that failed in the persistent weak layer of faceted snow also involved serious injuries. The avalanche was 1-2' deep and 600' wide.

(rescue from Pink Pine, pc: Wasatch Backcountry Rescue)

Yesterday, a skier high on Superior above Little Cottonwood Canyon unintentionally triggered a soft slab of wind drifted snow 1' deep and 70' wide. This was on a steep southwest facing slope at roughly 11,000'.

Also yesterday, near Grandview Peak, a snowmobiler remotely triggered (triggered at a distance) a soft slab failing on our PWL (persistent weak layer) of weak faceted grains. The avalanche was on a steep northeast facing aspect at 9200' with estimated dimensions of 2' deep and 300' wide. (photo below)

There were other avalanches this past week that occurred at low elevations below 8,000, including Lambs Canyon, Daly Canyon, and Summit Park.

Check out all the avalanches HERE and if you see an avalanche, please report it.

Snow and Weather

Skies are clear. Mountain temperatures are in the single digits. Winds picked up out of the northwest around dinner time last night, blowing 15-20mph with gusts to 30mph. The highest elevation anemometers recorded hourly averages of 35-40mph with gusts to 50. Riding conditions are nothing short of sublime although solar aspects will have a thin crust this morning before it thaws.

WOW, what a storm. Snowfall totals since Sunday night include:

Cottonwoods: 2.5' - 6' snow containing 1.5" - 2.75" SWE (snow water equivalent)
Park City: 1.5' - 3' snow containing 1" - 1.5" water SWE

For today, it'll be severe clear with light northwest winds. Temperatures will warm to the upper teens and low 20s.

Get caught up in significant weather and avalanche activity over this past week by reading our Week in Review.

Additional Info

Mark Staples has also written a season summary HERE.

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