Bollettino valanghe

Provo

Pubblicato il Jan 1, 2020valido fino al Jan 2, 2020Utah Avalanche Center

Pericolo valanghe

Alta quota
Limite del bosco
Sotto il limite del bosco

Non aggiornato — questo bollettino è scaduto 7 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Avalanche danger is on the RISE today. Today is simple, heavy snowfall and high winds will create avalanches. Avalanche danger will rise to CONSIDERABLE on all mid and upper elevation aspects and MODERATE on all lower elevation aspects.

Expect sensitive storm snow and wind drifted snow. Both human-triggered and natural avalanches are likely especially as the snowfall intensifies. Avoid being on or underneath slopes steeper than 30 degrees, and avoid avalanche runout zones.

Avalanche danger could increase to HIGH today, look for signs of rapidly changing conditions. Evaluate snow and terrain carefully. Use caution while route finding, and make conservative decisions.

Problemi valanghivi

Storm Slabs
N
NE
E
SE
S
SW
W
NW
Alta quota
Limite del bosco
Sotto il limite del bosco
Probabilità
Likely
Dimensione
2
Before the coming storm, we had beautiful low-density cold smoke. After a few days of cold days and no wind, the surfaces have maintained soft snow. The sluffs were running long and fast indicating weak snow and a variety of smooth bed surfaces exist. Add new snow and wind and we have a pretty straight forward problem on our hands, a wet and warm slab on top of that weaker layer of snow. Heavy snowfall will create sensitive storm snow today, including storm slabs as well as loose snow avalanches.

Human triggered avalanches are likely, as well as natural avalanches, especially during any period of high precipitation intensity and increased winds. Pay attention to rapidly changing conditions, and watch for and avoid slopes with cracking, avalanching, even on smaller slopes. These avalanches may be triggered at a distance, particularly during periods of high snowfall intensity.

Avalanche danger will be on the RISE today.
Wind Slabs
N
NE
E
SE
S
SW
W
NW
Alta quota
Limite del bosco
Sotto il limite del bosco
Probabilità
Very Likely
Dimensione
2
Today's strong westerly winds, which could be gusting up at 75 mph at ridgetops, will have plenty of new snow to work with, creating fresh wind drifts on all aspects at the mid and upper elevations. These wind drifts will be most pronounced near ridgelines and on easterly and southerly facing terrain where the new snow will be deposited. Watch for sensitive cornices along upper elevation ridgelines, give cornices a wide berth as they can break back farther than expected.

Additional wind loading will just increase our problem of a strong slab, over weak snow. The snowpack becomes a game of Jenga in which we have removed the bottom pieces, and just keep adding more to the top. Too much load on top of the weak base and it will topple over.

Look for signs of wind drifted snow, such as soft pillows, cracking, and whumphing and avoid them.
Persistent Slabs
N
NE
E
SE
S
SW
W
NW
Alta quota
Limite del bosco
Sotto il limite del bosco
Probabilità
Possible
Dimensione
3
We haven’t seen any activity on this layer for over 10 days now. This layer has been mostly dormant and has been gaining strength, but it is not forgotten. This storm system will be a good test of this layer.

With enough snow and wind, it is possible that new avalanches may step down into the old persistent weak layer. An avalanche in the persistent weak layer is most likely on repeater avalanche paths, generally shallower snowpacks and in steep thin rocky terrain.

Hopefully, this storm will be the telltale that lets us put this layer to rest for a while.

Special Announcement

Get discount lift tickets HERE. Thanks for this generous support from Utah Ski Resorts and Ski Utah. All proceeds go directly to supporting the UAC.

Landmines - Notes from an Army officer frequently deployed to the middle east who is also a skier living in Utah.

Podcasts - Check out two recent ones with Doug Workman and Jenna Malone.

Recent Activity

Human triggered sluffing still noted on the steepest slopes. Zinnia Wilson and Drew toured up around the UFO Bowls on Monday and our observation is here.

Snow and Weather

This morning, mountain temperatures are in the mid-20s F at trailheads and low 20s F at ridgetops. Winds are westerly and light in the valley, but increasing rapidly at ridgetops with gusts up to 60 mph. Light snowfall began around 5:00 AM with trace amounts of snow so far.

Today, the bottom line is that it's going to snow and it's going to blow. Initially, the snow will fall with warmer temperatures and high densities, bringing about 4-6 inches of 8-10% snow to the Provo area mountains by the early afternoon. Then temperatures will begin to drop and we will transition to a cooler northwest flow, bringing another 3-5 inches of lower density snow. On top of the increased snow amounts, winds will continue to be strong and westerly averaging 20-35 mph with gusts up to 75 mph at ridgetops.

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