Provo Avalanche Advisory

Forecaster: Bruce Tremper

BOTTOM LINE

Danger by aspect and elevation on slopes approaching 35° or steeper.
(click HERE for tomorrow's danger rating)


Danger Rose Tutorial

Although the danger is mostly Low (Level 1) today, there are pockets of Moderate (Level 2) danger in the following terrain: 1) any steep slope with recent wind deposits, 2) any sun exposed slope that is getting wet, and 3) steep terrain above about 9,500’ especially where the rain crust is thinner. Be advised, the danger is much higher in the Uinta Mountains so be sure to check their advisory before you go.

CURRENT CONDITIONS

Yesterday was one of those days you’re glad to be alive and living in paradise. Today should be a repeat with a foot of fine powder on a rock-hard ice crust. The sun exposed slopes will be crusty today and there is a bit of wind damage up high along the ridges. Temperatures have warmed to the mid teens and winds remain light to moderate from the northwest. An inversion layer up to 10,000 allowed winds to remain light below that elevation but the 11,000’ peaks the winds were quite strong, up to 60 mph from the northwest.

RECENT ACTIVITY

For the most part, the snow was well behaved yesterday, at least in the Wasatch Range but not in the Uintas (see below). In the Wasatch Range, someone noticed a snowmobile-triggered, soft slab south of Alta in Dry Creek where they triggered a 2’ x 40 foot soft slab on a high mark on an east facing slope. I’m assuming it was a wind slab near the ridge. Of more concern, we received at least 6 reports of collapsing into the weak snow under the rain crust and almost all were on southeast facing slopes above 9,500’. None of these slid but if they were on steeper slopes they would have. Finally, there were several loose, sluffs of the new snow on the steep, slick, ice crust, especially on south facing slopes as they heated up in the sun.

In the Smith-Moorhouse area of the Uinta Mountains a skier remotely triggered a deep hard slab 1-3’ deep, 1000’ wide failing on preserved surface hoar under a thin rain-rime crust. It was on a NE facing slope at 9,700’. The group experienced multiple collapses during the day.

THREAT #1
WHERE PROBABILITY SIZE TREND
      Over the next 12 hours.

The largest concern today is for wind slabs, mostly near the upper elevation ridges. We’re expecting the winds to remain light today but pick up tonight as a weak system passes to our north. If the winds pick up sooner than expected, there is a lot of loose snow to blow around and wind slabs will instantly form. Wind slabs will definitely be a problem on Saturday. These will all form on a slick, hard bed surface, making them long-running and fast. As always, avoid steep slopes with recent wind deposits.

THREAT #2
WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

Numerous reports of collapsing mean that not all is well in the hidden world buried beneath the perfect façade. Most of the reports came from southeast facing slopes above 9,500’. I have noticed that since the winds came from the west during the rain storm, the rain crust is thinner on the east facing slopes and in the trees. So the crusts don’t support your weight as much and the rain did not destroy the pre-existing, weak, faceted snow or surface hoar. Still, I don’t think we will see too many releases breaking below the rain crust, but collapsing is a sure sign that it’s still possible. Continue to be suspicious of upper elevation terrain, especially above 10,000’. As noted above, the Uinta Mountains are much more dangerous than the Wasatch Range for these deep, persistent slabs. So if you are headed that way, be sure to check the Uinta advisory.

THREAT #3
WHERE PROBABILITY SIZE TREND
      Over the next 8 hours.

With continued warming today and continued strong sun, we will likely continue to see wet sluffs and occasional wet slabs within the new snow, sliding easily on the hard rain crust. As usual, get off of steep slopes when they start to get soggy.

MOUNTAIN WEATHER

Today should be another nice day but with a few lingering clouds around the mountains this morning. Temperatures will be much warmer—into the mid 20’s along the ridge tops and the mid 30’s down at 8,000’. Winds should remain light but they will pick up tonight with the arrival of a system going by mostly to the north of us but we should be able to pick up 4-7 inches of new snow tonight and on Saturday. Tonight and Saturday, winds should blow 25-35 with gusts into the 60’s from the southwest, switching to the west and northwest.

The extended forecast is for a stong ridge to build in after the weekend and we will return to smog in the valleys and warm, sunny weather in the mountains for at least a week.

GENERAL ANNOUNCEMENTS

If you trigger an avalanche in the backcountry - especially if you are adjacent to a ski area – please call the following teams to alert them to the slide and whether anyone is missing or not. Rescue teams can be exposed to significant hazard when responding to avalanches, and do not want to do so when unneeded. Thanks.

Salt Lake – Alta Central (801-742-2033)

Ogden – Snowbasin Patrol Dispatch (801-620-1017)

Provo – Sundance Patrol Dispatch (801-223-4150)

Discount Lift tickets: Ski Utah, Backcountry.com, Alta, Deer Valley, Park City, The Canyons, Wolf Mountain, Snowbasin, Beaver Mountain, Brighton, Sundance, and Solitude have donated a limited number of tickets for sale.

Wasatch Powderbird Guides flight plan.

Dawn Patrol Forecast Hotline, updated by 05:30: 888-999-4019 option 8.

Daily observations are frequently posted by 10 pm each evening.

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UDOT canyon closures UDOT at (801) 975-4838

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The information in this advisory is from the U.S. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur.

We will update this forecast tomorrow morning. Thanks for calling.

This information does not apply to developed ski areas or highways where avalanche control is normally done.  This advisory is from the U.S.D.A. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur.

This advisory provided by the USDA Forest Service, in partnership with:

The Friends of the Utah Avalanche Center, Utah Division of State Parks and Recreation, Utah Division of Emergency Management, Salt Lake County, Salt Lake Unified Fire Authority and the friends of the La Sal Avalanche Center. See our Sponsors Page for a complete list.