Bollettino valanghe

Ogden

Pubblicato il Feb 24, 2024valido fino al Feb 25, 2024Utah Avalanche Center

Pericolo valanghe

Alta quota
Limite del bosco
Sotto il limite del bosco

Non aggiornato — questo bollettino è scaduto 3 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Today, the avalanche danger is MODERATE across mid and upper-elevation slopes facing east, southeast, south, southwest, and west where triggering a persistent weak layer avalanche that breaks to a crust with faceted snow 1-3 feet deep is possible. Additionally, there is a MODERATE avalanche danger across all upper-elevation terrain for both hard or soft slabs of wind-drifted snow. On slopes facing southwest through south and southeast, the avalanche danger will rise to MODERATE as the snow surface heats up, potentially leading to small wet-loose avalanches on solar aspects. On mid and upper-elevation slopes facing southeast, any wet avalanches may trigger larger slab avalanches, failing on the persistent weak layer (PWL). The remaining aspects have a LOW avalanche danger.

It's crucial to carefully evaluate snow and terrain today, identifying potential hazards, as human-triggered avalanches are possible.

Problemi valanghivi

Persistent Slabs
N
NE
E
SE
S
SW
W
NW
Alta quota
Limite del bosco
Sotto il limite del bosco
Probabilità
Unlikely
Dimensione
2
On certain 'solar' slopes, particularly those facing east and southeast, there is a persistent weak layer (PWL) of facets just above a crust that was buried by storms beginning February 14th. As the warm weather and clear skies persist, the likelihood of triggering an avalanche on this layer will continue to decrease, and for the Ogden area is already very low, and the lingering facets that do exist will continue to heal. Personally, I'm addressing this issue by avoiding these slopes and opting for northerly facing slopes where the snow quality is superior and this avalanche problem doesn't seem as much of an issue.

Mark discusses the avalanche problem that is primarily isolated to the East and Southeast facing aspects.

While we are beginning to consider shrinking this avalanche problem, as it appears to be primarily isolated to southeast through east-facing aspects. However, there is still a chance of encountering this layering and issue on western-facing aspects, though the likelihood is significantly lower compared to the aspects facing southeast and east.
Loose Wet
N
NE
E
SE
S
SW
W
NW
Alta quota
Limite del bosco
Sotto il limite del bosco
Probabilità
Likely
Dimensione
2
Strong sunshine and warm temperatures will trigger wet-loose avalanches on steep, sunny slopes. On mid and upper elevation slopes facing southeast, any wet avalanches may trigger larger slab avalanches, resulting in failure on the persistent weak layer (PWL).

Wet snow is the easiest avalanche problem to avoid; simply move to shady slopes once the snow surface becomes wet. Look for signs that the snow surface is becoming wet, such as rollerballs and pinwheels. Remember, even a "small" avalanche can be deadly in consequential terrain.
Wind Slabs
N
NE
E
SE
S
SW
W
NW
Alta quota
Limite del bosco
Sotto il limite del bosco
Probabilità
Possible
Dimensione
2
With strong winds last week, stubborn slabs of wind-drifted snow are likely to be encountered on all upper-elevation slopes and some mid-elevation terrain features that allow for drifting snow accumulation. Some of these wind drifts may be reactive if they formed on top of graupel. The graupel layers vary, but they can often be found below steeper cliff bands where graupel can accumulate.

These drifts could be 1-3 feet deep and up to 150 feet wide. Watch out for signs of wind-drifted snow, such as pillow-shaped deposits, and avoid those slopes. Any recent wind drifts were covered by snowfall Wednesday night, so you will need to dig down to search for them.

Give cornices a wide-bearth as they continue to grow.

Recent Activity

Avalanche activity yesterday primarily included cornice fall and long-running sluffs, as well as some larger avalanches in the Central Cottonwoods failing on two different layers of buried persistent weak layers

On Thursday evening, a very large avalanche occurred on Miller Hill in American Fork Canyon. One or two people were likely caught in the avalanche. However, they were gone when the second group arrived and conducted a beacon search to ensure no one was buried. It appears that at least one snowmobile was caught and partially buried, and there was supposedly another hole where another snowmobile might have been partially buried. It's unclear if anyone was injured, but we're relieved there were no serious injuries that would have required Search and Rescue. Mark Staples visited the avalanche yesterday; it was approximately 1,500 feet wide and 2 feet deep, and it broke on a layer of faceted snow above a crust.

Snow and Weather

This morning, under clear skies and nearly a full moon, there is a temperature inversion in the mountains, with trailhead temperatures in the upper teens, and ridgetop temperatures near 20 F. Winds are from the west and light through the mid-elevations, with gusts up to the mid-30s mph at upper elevations.

Today will be another day of strong sunshine, with temperatures warming into the upper 30s F at upper elevations and the mid-40s F at low and mid-elevations. Winds will remain from the west and continue to be generally light to moderate, with gusts near 35 mph at upper elevations.

Outlook: The weekend remains sunny. Snow is expected to start late Monday morning or early afternoon, heaviest in areas with southwest flow. Before the cold front, snow levels will be around 6500 to 7000 feet and denser. A strong cold front will move through Monday night into Tuesday morning, bringing strong winds and heavy snow. Temperatures will drop quickly. Snowfall rates of 1 to 2 inches per hour are likely along and behind the front. Snow will continue into early Wednesday, with some models suggesting it may end before midnight Tuesday. This next storm could bring 15-20 inches of snow to the Ogden Area Mountains.

Travel and riding conditions are superb, although some slopes may be crusted this morning due to the strong sunshine yesterday and some greenhousing on Thursday.

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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.

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