Uintas Avalanche Advisory

Forecaster: Craig Gordon

BOTTOM LINE

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


Danger Rose Tutorial

At and above treeline in mid and upper elevation terrain a Level 3 (CONSIDERABLE) avalanche danger exists for both new and older windslabs. These will be sensitive to the additional weight of a rider and human triggered avalanches are likely, especially on slopes facing the north half of the compass. In addition, cornices have grown ginormous and are breaking back much further than you might expect.

A Level 3 (CONSIDERABLE) avalanche danger exists on mid and upper elevation slopes facing West, Northwest, North, Northeast, and East due to the threat of a deep slab avalanche breaking below the January raincrust. While the chances of triggering it are isolated, if you do, you're looking at a large, dangerous and potentially un-survivable avalanche.

Out of the wind on low angle slopes the avalanche danger is a Level 1 (LOW) danger.


CURRENT CONDITIONS

Skies are clearing in the wake of yesterday’s storm which turned out to be more blow than snow. It does look, however, like most areas picked up 2”-4” of medium density snow. Southerly winds have punished the range the past 24 hours, blowing in the 50’s and 60’s with gusts near 90 mph along the high ridges. They’ve calmed down somewhat and are currently blowing 15-30 mph, gusting in the 40’s near the highest peaks. Temperatures have cooled into the low to mid 20’s.Riding and turning conditions are going to be variable to say the least. But, among all the wind jacked snow and breakable crust you’ll still be able to find some soft snow in very wind protected, mid elevation, north facing terrain. Or you could take the day off, get your taxes in order, and wait for Monday’s storm.


RECENT ACTIVITY

We heard about two avalanches yesterday, both involving the tremendous amount of snow getting blown around by the strong winds. Ted and Justin found one natural which occurred in Millcreek on a steep, Northeasterly facing slope at about 10,000’. The slide was 2 ½ ‘deep, 300’ wide, running 600’ vertically.

In upper Weber Canyon a rider triggered a hard slab that broke on a low angle, 31 degree slope, after 10 other people had already crossed the slope. This avalanche occurred on a heavily wind loaded Northeast aspect at about 9,700’. The slab was 3’ deep, 100’ wide, and only ran about 100’ vertically into a group of trees. Fortunately everyone came out unscathed, but they were certainly rattled by the event.

Click here for more western Uinta observations.


THREAT #1

WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

Yesterday’s winds drifted a tremendous amount of snow, creating widespread hard slabs all over the map, loading terrain we usually go to because it’s safe. With a few inches of snow helping to cover over and disguise these drifts, you’ll have to have a keen eye and carefully evaluate your terrain choices, especially as you change aspect or travel from one drainage to another. Today, tweak test slopes like road cuts and get a solid feeling for how the snow is reacting to your additional weight before getting into big terrain. Look for clues to unstable snow like cracking, collapsing or whoomphing sounds, and of course the hugest clue…. recent avalanches on slopes similar to what we wanna ride on. It’s tricky out there and as evidenced by yesterday’s events, it may not be the first person on the slope that triggers the slide. As always, think about your terrain choices and the consequences of triggering a slide.


THREAT #2

WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

On Friday, Grant and Ted initiated a surface hoar research project on the North Slope. They dug in a variety of locations, conducted a wide array of tests, and were unable to get the surface hoar to react. So you’re probably asking yourself, where does this leave us after yesterday’s huge wind event? Unfortunately we’re in a scary grey area of forecasting- the classic low probability, but high consequence scenario that keeps forecasters up at night. While the chances of triggering an avalanche failing in the surface hoar are isolated, if you do, it will likely be a large, destructive, and potentially un-survivable event.

So how do you ride safely with odds like that? When the stability is in question, the answer can always be found in terrain. Sticking to lower angle, more wind protected mid elevation slopes, will minimize your exposure to the danger and you’ll still be able to rip it up all day and not have to worry about avalanches. Sounds like a pretty good deal to me.


THREAT #3

WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

Cornices are huge and are breaking much further back than you might expect.


MOUNTAIN WEATHER

After a brief break in the action this morning, clouds should increase throughout the day as another wave of the Pacific trough moves inland. Temperatures remain mild with highs reaching into the low to mid 30’s and overnight lows dipping into the low 20’s. Southerly winds remain in the 15-30 mph range this morning, but should begin cranking again late in the day, blowing in the 50’s, gusting into the 70’s on Monday. Another shot of moisture slides through the region Monday with the potential to deliver 5”-10” of snow. A slight break in the action with more storms lined up for later in the week.


GENERAL ANNOUNCEMENTS

The information in this advisory expires 24 hours after the date and time posted, but will be updated by 7:00 AM Wednesday, Mar. 23th, 2011.

If you’re getting out and about and trigger an avalanche or see anything interesting please let us know here. Or drop Craig an email : craig@utahavalanchecenter.org or call 801-231-2170

The western Uinta advisory program is going full tilt and forecasts will be issued by 7:00 AM on Wednesday, Saturday, Sunday and all holidays.


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.