Lawinenlagebericht

Provo

Veröffentlicht am Dec 25, 2021gültig bis Dec 26, 2021Utah Avalanche Center

Lawinengefahr

Hochgebirge
Waldgrenze
Unterhalb der Waldgrenze

Veraltet — dieser Lagebericht ist 5 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

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 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.

Increasingly dangerous avalanche conditions are expected for Sunday with heavy snowfall and strong winds forecasted.

Lawinenprobleme

Persistent Slabs
N
NE
E
SE
S
SW
W
NW
Hochgebirge
Waldgrenze
Unterhalb der Waldgrenze
Wahrscheinlichkeit
Very Likely
Größe
4
Recent 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.

We have overloaded this weak layer with strong west/southwest winds and snowfall containing over 2" of water weight, creating dangerous avalanche conditions where this PWL is present.

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
Hochgebirge
Waldgrenze
Unterhalb der Waldgrenze
Wahrscheinlichkeit
Likely
Größe
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
Hochgebirge
Waldgrenze
Unterhalb der Waldgrenze
Wahrscheinlichkeit
Possible
Größe
2
You may find sensitive slabs of soft snow today, especially in areas that received the most snow, such as upper Little Cottonwood. Although we are only expecting snow showers today, an increase in snowfall intensity can quickly make the new snow reactive.

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.

Recent Activity

The northeast chute of Elk Point had at least one natural avalanche, likely Thursday night or Friday morning, during the period of heaviest precipitation intensity. Another avalanche (likely a natural) was reported from Upper Dry Creek on Timpanogos on a southeast aspect. Although the avalanche was observed from a distance with poor lighting, the crown was estimated between 2-6' deep and 250' wide.

Resorts from the Salt Lake mountains saw significant avalanche activity on northerly slopes breaking into old snow. Control workers triggered deep, hard slab avalanches both remotely (from a distance) and sympathetically - where one avalanche triggers another. Crowns were generally 2-4' deep, but some exceeded 6', breaking out several hundred feet wide.

One skier-triggered backcountry avalanche was reported from the Salt Lake mountains in the Red Pine trees on an east aspect at 9,100'. The avalanche was 2' deep and 80' wide, breaking down into old, faceted snow. Fortunately no one was caught. I encourage you to read their honest and humble observation which describes so many different "human factors" at work. I especially appreciate this group's assessment and how this avalanche occurrence will affect future decision-making. Thank you for the observation and thoughtful write-up.

Although specific to the Salt Lake mountains, 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

Winter Solitude

in a world of one colour

the sound of the wind.

- Bashō

Very strong winds from the west/southwest at all elevations highlight the weather this morning.

At the highest ridgelines winds are averaging in the 40's and 50's mph with gusts in excess of 100 mph;
mid-elevation wind speeds average in the teens and 20's with gusts in the 40's mph;
low-elevations are seeing gusts in the 20's and 30's (and, yes, 40's) mph.

Temperatures range through the 20's F.

Anywhere from 2-6" new snow reported from overnight, although such strong winds make accurate reporting challenging. Since Friday morning the Provo mountains have received 10-15" of snow containing 2.4" of water.

For today, strong west/southwest winds will continue. At the mid elevations winds will average in the teens and 20's with gusts in the 40's mph. Highest elevations will experience wind speeds averaging in the 30's with gusts in the 60's mph. A few inches of snow is likely throughout the day. Temperatures will rise into the 20's and low 30's F.

Snowfall and moderate to strong winds overnight with a sharp cold front on Sunday morning with heavy snowfall forecasted for Sunday.

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