The Utah Avalanche Center has issued an AVALANCHE WARNING for the Provo area. Strong wind over the past few days, along with heavy dense snowfall, has created very dangerous avalanche conditions. The avalanche danger is HIGH, and traveling in or under avalanche terrain is NOT recommended.
South wind has blown for 60 straight hours at speeds of 10-25 mph with gusts into the 20s and 30s. These are the perfect speeds for drifting snow onto lee slopes. These winds, combined with feet of dense, heavy snowfall, have created monster soft and hard slabs of wind-drifted snow in the starting zones. These will not be small avalanches. These avalanches can run long distances into the valleys below.
I would imagine the new snow is settling and bonding rapidly. However, it's just now stopped snowing, and I think it needs more time to adjust to the rapid loading event over the past few days of heavy snowfall. Soft slabs 1-3' deep will be found in steep terrain today.
If you think this layer is gone, I challenge you to get your shovel out and dig. I can find this layer everywhere: Skyline, Provo, Wasatch Back, SLC, Parkcity Ridgeline, Millcreek, Lambs, Sessions, Bountiful, Farmington, and Ogden.
This persistent weak layer of faceted snow is now roughly buried 2-6 feet deep with a very thick hard slab above it. Yes, the weak layer is gaining some strength. Yes, it's becoming harder to trigger this layer. However, if you do trigger an avalanche that breaks to this layer, it's likely to be a season-ender or worse. With so many close calls over the past few days, I am worried our luck will run out, and today through this weekend has accident written all over it. We could almost start writing the accident report now.
With the recent loading event, there is only one option in my mind, and that is to avoid avalanche terrain.
What: Strong wind over the past few days, along with heavy dense snowfall, has created very dangerous avalanche conditions. The avalanche danger is HIGH, and traveling in or under avalanche terrain is NOT recommended.
When: In effect until 6:00 AM MST Friday.
Where: For the Wasatch Range south of I-80, the Western Uinta Mountains, the Wasatch Plateau and Skyline Mountains of central Utah, the Abajo mountains in southeast Utah, and mountain ranges in southwestern Utah including the Tushars and areas near Cedar City.
Impacts: Several days of strong south wind and heavy snowfall are causing large and dangerous avalanches that are running far downhill. Avoid being on or under any steep slope where avalanches run. Dangerous avalanche conditions are expected to last through the weekend.
Yesterday, the precipitation intensity spiked with rates well over 1" per hour snowfall, and the Provo area went through a widespread natural avalanche cycle. Below is a picture from Rock Canyon with debris 20 feet deep. This avalanche started way above and traveled thousands of feet downhill (pictures below).
I can't say I am ever excited for it to stop snowing, but that was an intense few days here. Storm totals for the past 24 hrs are roughly 10-17 inches of new snow (0.55-2.28" water) for the Wasatch Mountains.
This morning, it's snowing, and mountain temperatures are cold and range from 19-25 °F. Winds have finally calmed down and blow from the northwest at 5-15 mph across the upper elevations. As one storm exits, another is spinning over Sin City, which will bring light snow showers to the mountains today. Accumulations will be in the 2-6 inch range. Winds are forecast to be light and from the southwest with speeds of 5-15 mph. One more small storm Friday into Saturday before we clear on Sunday.
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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.
