Provo Avalanche Advisory

Forecaster: Drew Hardesty

BOTTOM LINE

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


Danger Rose Tutorial

The danger is CONSIDERABLE on all mid and upper elevation north through east facing slopes steeper than 30 degrees. The west and southeast slopes are similar, but more pockety in nature. If you’re in this terrain, it’s probable that YOU will trigger a large, unmanageable avalanche. You may not get a second chance. The gentler slopes on the southerly aspects remain the ticket for the prudent skier or rider.

CURRENT CONDITIONS

Trailbreaking and riding conditions improved dramatically with natural settlement over the last 24 hours. With the blockbuster storm not yet a distant memory, skies are clear and mountain temperatures are down in the single digits and low teens. The winds are back to the southwest, blowing 15-20mph with gusts to 30.

RECENT ACTIVITY

Collapsing and remotely triggered slides continue to be the rule and not the exception. The strengthening slab now propagates the thunderclaps over much longer distances, shooting cracks push distances of up to 350’, and remotely triggered slides release from up to 100’ away. “Spooky”, “Twitchy”, and “Hair-raising” have all been used to describe what we’re seeing out there. Of course we knew this was coming.

In the Brighton backcountry, a party likely unintentionally triggered a 2-3’ deep and 100’ wide soft slab on a north facing slope at 9500’ near the Pioneer ridge. Snow plows and cats remotely triggered slides into the older faceted snow, with the slide at Sundance in Provo perhaps one of the more interesting avalanches in years. It broke out 3’ deep and 500’ wide, running only 30’ – as it was on a 28-33 degree slope. Not only do the Provo mountains have the weak faceted snow from Oct/Nov, but they piled nearly 4’ of 14% on top of 2’ of 4% snow. I don’t believe we’re done. Not by a long stretch. Click on Current Conditions (found on the upper left hand corner of the screen) for yesterday's photos and observations.

THREAT #1
WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

Now is when it starts to get interesting. I’ve put a graph on the web here that outlines part of my theory on why an accident is likely to occur today. Collapsing and shooting cracks will still be prevalent – nope - not much has changed in the last 24 hours – and avalanches may still be triggered at a distance. The stiffening overlying slab may start to pull into lower angled terrain and wrap around terrain features on adjacent slopes. Remember that under these circumstances, safe runout zones may NOT include leaving the runout of your line to get underneath another.

And, from yesterday as The Song Remains the Same: The backcountry remains dangerous. Collapsing and remotely triggered slides, while not as prevalent as during Sunday’s onslaught, will still be likely on a variety of elevations on the shady aspects. The new snow has likely gained strength, but it’s like rebuilding a nice house over a rotten foundation. It’s bound to come crashing down again. Tests on the snow will continue to reveal good propagation at the facet interface, now buried 2-4’ down.

THREAT #2
WHERE PROBABILITY SIZE TREND
No trend identified.

The increasing southwesterly winds will likely foster new soft slab development along the upper elevation lee terrain. Watch for and avoid any new rounded pillows or scalloped drifts primarily in the steep north and east facing slopes.

MOUNTAIN WEATHER

Increasing cloud cover will herald the moist westerlies passing to our north and the Logan mountains may even see an inch or two by late tomorrow. Increasingly milder temps will push 8000’ temps to the upper 30s and the 10k temps to the upper 20s. Winds will remain from the west and southwest blowing 20-25mph. The forecast into the weekend and beyond looks decidedly uninspiring.

GENERAL ANNOUNCEMENTS

The Wasatch Powderbird Guides are up and running. Go to their blog to see their operation schedule today.

We are recording our early morning phone line, (1-888-999-4019, option 8), with avalanche information, by 5:30 am – it’s a good source for dawn patrollers. Also, many of the day’s observations are posted on line under Current Conditions by 10 pm each evening.

Pro Riders Workshop at Snowbird The Utah Avalanche Center and Snowbird Ski and Summer Resort are partnering to offer the first annual Freeride Avalanche Summit, Dec.17-18. The two-day clinic targets advanced and expert skiers and riders who want practical and professional instruction on avalanche awareness, safety and rescue. The Freeride Avalanche Summit includes a unique blend of instruction that combines the expertise of industry leading avalanche forecasters with the experience and influence of local, professional athletes. Click here for more info and to register- http://www.snowbird.com/freerideavalanchesummit.html

Our web site is now formatted for iPhone. You can also download a free iPhone application from Canyon Sports to display the Bottom Line. Search for Utah Avalanche on the Apple's iPhone Apps page or in iTunes.

If you want to get this avalanche advisory e-mailed to you daily click HERE.

For a text only version, the link is on the left side bar, near the top.

UDOT highway avalanche control work info can be found by calling (801) 975-4838. Our statewide toll free line is 1-888-999-4019 (early morning, option 8).

Donate to your favorite non-profit – The Friends of the Utah Avalanche Center. The UAC depends on contributions from users like you to support our work. To find out more about how you can support our efforts to continue providing the avalanche forecasting and education that you expect please visitour Friends page.

We appreciate avalanche and snow observations. If there’s something we should know about give us a call at (801) 524-5304 or 1-800-662-4140, or email us at uac@utahavalanchecenter.org. (Fax 801-524-6301).

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.

Evelyn Lees will update this forecast on Wednesday morning. And 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.