Bollettino valanghe

Provo

Pubblicato il Jan 11, 2023valido fino al Jan 12, 2023Utah Avalanche Center

Pericolo valanghe

Alta quota
Limite del bosco
Sotto il limite del bosco

Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

The avalanche danger is HIGH at all upper and mid elevations where heavy snowfall, heavy rain, and strong winds have created very dangerous avalanche conditions. New snow and wind-drifted snow avalanches may step down into older facets, leading to large and destructive avalanches.

The avalanche danger is HIGH at all lower elevations due to the overhead hazard and heavy rain. Yesterday, a very large hard slab avalanche hit the Provo River.

Avoid travel below steep terrain as avalanches have the potential to run into lower elevation flat areas near trailheads or overrun ice climbing routes.

Problemi valanghivi

Wind Slabs
N
NE
E
SE
S
SW
W
NW
Alta quota
Limite del bosco
Sotto il limite del bosco
Probabilità
Very Likely
Dimensione
3
With a huge bump in northwest winds overnight, gusts up to 90 mph, and so much soft snow available for transport, you are likely to find sensitive slabs of wind-drifted snow on all mid and upper-elevation slopes. The new soft slabs will be most pronounced on lee-ward facing slopes, but elevated winds can load any aspect because winds swirl and change direction as they pass through the mountains, this is known as cross-loading.

Look for cracking, collapsing, and rounded pillows of new snow and avoid steep terrain where you could trigger them.

Any wind-drifted avalanche may step down into a deeper buried weak layer resulting in a larger avalanche.

Example of the soft slab avalanches of wind drifted snow you could find today. Brighton Hill - B. Nalli. Find full observation HERE.
Storm Slabs
N
NE
E
SE
S
SW
W
NW
Alta quota
Limite del bosco
Sotto il limite del bosco
Probabilità
Very Likely
Dimensione
3
Storm totals of 15-30" of new snow over the past 24 hours will create both sensitive soft slabs of new snow and fast, long-running sluffs on all aspects at mid and upper elevations. While new snow avalanches can be consequential on their own - the primary concern is if they step down into the buried persistent weak layer.

I suspect at lower elevations where it is warmer the new snow is bonding quite well to the old snow surface.
Persistent Slabs
N
NE
E
SE
S
SW
W
NW
Alta quota
Limite del bosco
Sotto il limite del bosco
Probabilità
Unlikely
Dimensione
4
The deeply-buried persistent weak layer (PWL) from November continues to gain strength and it has become harder to initiate an avalanche on this layer. It may take a significant trigger - this could include a large cornice fall, multiple riders on a slope at a time, or another avalanche adding more weight to the snowpack, and stepping down to trigger this layer. Any avalanche triggered on this weak faceted snow would be 2-7' deep. Areas where you are more likely to trigger this PWL, are shallow thinner spots, rocky ridges, and mid-elevation terrain.

This report from Parley's Canyon still shows weak faceted snow buried under 3' of harder-density snow.

Recent Activity

The Provo area mountains went through an impressive natural cycle yesterday morning. Including large hard slab avalanches as well as wet-loose avalanches. One of the most impressive being Bridalviel falls. That naturalled and hit the Provo river.

Ski areas saw long-running wet loose avalanches.

Find all recent avalanches HERE.

Snow and Weather

Overnight mountain locations reported 6-9" of new snow and .90-1.62" of water. Storm totals are up to 15-30" of snow. Currently, it is still snowing in the mountains, but the peak snowfall rates have passed.

This morning, trailhead temperatures are in the mid 20's F. Winds have transitioned to the northwest and are blowing 10-20 gusting to 30 MPH at the mid-elevation ridgelines. At the upper elevation ridgelines, winds are blowing 30 mph gusting near 90 mph.

Today willbring continued cloudy skies and snowfall this morning, before tapering off this afternoon. Temperatures will climb into the upper-20s and low 30s F and winds will remain elevated, but begin to decrease throughout the day, blowing from the northwest 15-25 mph with gusts up to 55 mph. We could see another 1-3" of accumulation before the high pressure moves into the area for Thursday and Friday before a more active pattern returns.

Overall water totals are impressive for the entire state, with snow water equivalent percent close to 200% in most areas.

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