Boletín de aludes

Provo

Publicado el Dec 28, 2019válido hasta el Dec 29, 2019Utah Avalanche Center

Peligro de aludes

Alta montaña
Límite del bosque
Bajo el límite del bosque

Desactualizado: este boletín caducó 7 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Today there is a MODERATE danger on all upper elevation terrain where the winds have increased and begun transporting snow and forming wind drifts. Look for signs of wind drifted snow in steep terrain and avoid them.

An isolated MODERATE danger exists for triggering an avalanche 2-5' deep on northwest through east-facing aspects at the upper elevations. Continue to avoid steep rocky terrain as well as shallow slopes that have already avalanched this season.

Low and mid-elevation bands are LOW where generally safe avalanche conditions exist, and human triggered avalanches are unlikely.

Problemas de aludes

Wind Slabs
N
NE
E
SE
S
SW
W
NW
Alta montaña
Límite del bosque
Bajo el límite del bosque
Probabilidad
Possible
Tamaño
2
Into the early afternoon yesterday and the evening, the winds began to pick up at the upper-most elevation band. This morning ridgetop winds are gusting above 30 mph. With a wide variety of surface conditions before this most recent storm, and 12"-16" inches of snow available to transport new drifts will have formed overnight. Winds are forecast to continue gusting near 30 mph at ridgelines, with plenty of snow to drift into these sensitive new wind slabs. Watch for plumes off the high peaks and blowing snow as these are obvious signs of wind-drifts forming.

The key is to identify and avoid any signs of wind drifted snow such as rounded, smooth or scalloped drifts on steep slopes.

At the mid-elevations some human triggered new snow avalanches could remain possible in cold, north-facing terrain that was sheltered from the wind. There's generally little mystery with these types of avalanches: they break at your feet or sled and respond to cornice drops and ski cuts. Keep an eye on your partners; carry and know how to use your rescue gear.
Persistent Slabs
N
NE
E
SE
S
SW
W
NW
Alta montaña
Límite del bosque
Bajo el límite del bosque
Probabilidad
Unlikely
Tamaño
3
We still have a potentially unstable snow structure of a strong slab over a persistent weak layer of faceted snow near the ground on upper elevation northwest through east facing terrain.

When will this layer go away? That is the true question, we are beginning to feel a bit better about the layer of facets on the ground at mid-elevations. We haven't seen avalanche activity on this layer in over week, the facets are no longer pouring out of the pit wall like sugar, and people are starting to push out onto some steeper terrain for the first time this season. Yesterday, after spending some time in the mid-elevation band, digging in multiple locations, and practicing safe travel techniques Trent said he skied his first north-facing slope over 36 degrees for the season. These are all good signs, but it doesn't mean we are in the clear. These facets are not yet dormant and still need time until they are no longer an issue. Every time we head into mid and upper-elevation north-facing slopes we need to evaluate snow and terrain very carefully.

The slopes that are the most suspect for this persistent weak layer, are very rocky places or places with a thin snowpack (less than a ski pole in depth). While out traveling look for signs of a shallow snowpack by probing the depth with your ski pole or probe.

If you choose to enter the terrain where this avalanche problem exists, look at the terrain below you, consider the consequences of triggering one of these large avalanches, and travel with a conservative mindset.

Photo of the snowpack Trent was able to find at 8500' in the Central Wasatch which had the poor snowpack structure, but no propagation in his stability tests.

When will this layer go away?

Info about this layer and where it exists

Snow and Weather

This morning temperatures are cold at trailheads, hovering in single digits. Ridgetop temperatures are in the negative single digits. Winds are northerly to northwesterly averaging in the single digits with gusts in the mid to upper 30s.

Since yesterday, the winds switched from the south and southeasterly to a cold northwest flow.

Today, temperatures should remain cold in upper teens to low 20s F, with a wind chill in the single digits. The wind speeds will remain calm at lower and mid-elevations. Skies will be broken with few small flurries but no real snow accumulation.

Skiing and riding conditions remain excellent on all aspects and elevations but for some slight sun/green housing damage on steep southerly aspects.

Special Announcement

New blog post-Landmines - With permission, we are reprinting a recent piece of correspondence from an Army officer who is frequently deployed to the middle east. Drew spent time in the middle east as a naval intelligence officer in Desert Storm in the early 90s.

New podcast - Risk, Reward, and the Big Lie - A Conversation with Ski Guide Doug Workman

Jenna Malone's UAC Podcast - Betting Your Life - Why Forecasting is Poker and Not Chess - A Conversation with Jenna Malone - now has her video presentation from this fall's USAW.

Thanks to the generous support of our Utah ski resorts and Ski Utah, we have discount lift tickets available. All proceeds from these go towards paying for avalanche forecasting and education! Get your tickets here.

Recent Activity

No reports of activity from the Provo mountains yesterday, but widespread sluffing and isolated soft slabs were noted in steeper terrain in the Central and northern Wasatch. Across the board, these sluffs and shallow soft slab avalanches were generally running in the old-snow interface on a bed surface comprised of temperature crusts and wind old slabs. While still being triggered, the sluffs are moving more slowly than the days prior.

Below is a point release triggered in Yellow Jacket which ran 800' down. See full observation on cycle in Millcreek and Alexandar Basin area. (Photo: Wilson/Gagne)

On Wednesday a snowboarder unintentionally triggered a storm slab in Dutch Draw roughly a foot deep and 150' wide. Yes, that Dutch Draw, the site of the fatality on the 15th and then kite-ski triggered avalanche a couple of days later. This avalanche was on east-northeast facing terrain at 10,000'. See the video below and full avalanche observation HERE.

General Announcements

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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