Uintas Avalanche Advisory

Forecaster: Craig Gordon

SPECIAL ANNOUNCEMENT

A Special Avalanche Advisory has been issued for the mountains of northern Utah including the western Uintas. Recent new snow, coupled with strong winds overloaded a variety of weak layers and dangerous human triggered avalanches are likely on steep slopes.


BOTTOM LINE

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


Danger Rose Tutorial

If your travels take you to the North Slope the avalanche conditions remain dicey. A HIGH (Level 4) avalanche danger exists on steep wind loaded slopes. Deep, dangerous and potentially unsurvivable human triggered avalanches are likely.

At mid and upper elevations elsewhere throughout the range the avalanche danger is generally CONSIDERABLE (Level 3) on steep wind drifted slopes and human triggered avalanches are probable. In addition, dangerous human triggered avalanches which break into weak snow near the ground are still probable and a CONSIDERABLE (Level 3) avalanche danger exists especially in steep, rocky terrain with a shallow snowpack, on slopes facing northwest through southeast.

Steep wind drifted slopes at lower elevations have a MODERATE (Level 2) avalanche danger and human triggered avalanches are possible.

A LOW (Level 1) avalanche danger exists, especially on sun exposed slopes and those not effected by wind.


CURRENT CONDITIONS

Skies are mostly cloudy and snow is at our doorstep as the last in a series of disturbances charges our way this morning. Temperatures are in the upper teens at 10,000’ and mid 20’s at the trailheads. Northwest winds gusted into the 30’s for a few hours late last night, before relaxing and switching more westerly and are currently in the 10-15 mph range. Riding and turning conditions have vastly improved the past few days, though winds raked the exposed upper elevation terrain.


RECENT ACTIVITY

The North Slope came unglued late Saturday and several large avalanches were reported in upper Weber Canyon and around the Mirror Lake Highway. The largest slide near 1000 Peaks Ranch occurred on an east-northeast aspect at 10,300’ in elevation, was 3’ deep, 400’-500’ wide, running 1000’ vertically, piling up close to 10’ of debris. Several smaller pockets ran naturally and a snowcat remotely triggered a cornice release which in turn pulled out an avalanche a couple feet deep and several hundred feet wide.

Near the Mirror Lake Highway the east side of Bald Mountain avalanched rather significantly, pulling out a large piece of snow from the hanging snowfield which crashed down on the aprons, running several hundred feet onto the flats. A large avalanche also occurred on the east face above Camp Steiner, one on the west side of Hayden Peak and a nice little two foot deep pocket over near Ruth Lake.

Click here for more details.


THREAT #1

WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

The natural avalanche cycle may be waning, but our structurally challenged snowpack remains sketchy at best, hanging in the balance waiting for a trigger like us to come along and tip the scales. Like a boxer on the ropes in the eleventh round, the snowpack is reeling from a one-two combination of strong ridgetop winds and new snow. As evidenced by our tree snapping natural avalanche cycle, avalanches are running for long distances, breaking wider than you might expect and failing on weak snow near the ground taking out the entire season’s snowpack. These slides are unpredictably large, very dangerous and unsurvivable. Today is not the day to be pulling on the avalanche dragons’ tail to see if it’ll bite back. You’ll need to continue avoiding steep slopes, avalanche runout zones and terrain traps like gullies and roadcuts.


THREAT #2

WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

Strong ridgetop winds were all over the map the during the storm cycle, whipping the new snow into fresh drifts, not only on the leeward side of ridges, but further downslope as well. Avalanche conditions will be changing throughout the day as new snow stacks up and gusty winds become a dominate player. Fresh wind drifts could get quickly out of hand once triggered today- stepping down into weaker layers of snow as they descend a slope, creating a larger slide than you might’ve bargained for. Terrain features like steep, rocky breakovers would be likely suspects. You’ll need to carefully evaluate each slope on an individual basis and be alert to red flags indicating dangerous avalanche conditions, especially as the day wares on. Remember- shooting cracks, collapses and whoomphing sounds are huge clues along with the most obvious sign of instability… recent avalanches on the same kinds of slopes you wanna ride.


MOUNTAIN WEATHER

Periods of heavy snow should be developing in the next couple of hours and we can expect a quick burst, stacking up 6”-8” by early afternoon. Westerly winds will gust into the 30’s along the ridges, becoming stronger around midday, before switching to the northwest and relaxing somewhat later today. High temperatures at 10,000’ will be in the low to mid 20’s and at 8,000’ near 30 degrees. Overnight lows under clearing skies dive into the low teens. Brief high pressure builds for Tuesday, giving us partly cloudy skies, light winds and crisp temperatures. An active weather pattern returns for the latter half of the week.


GENERAL ANNOUNCEMENTS

The information in this advisory expires 24 hours after the date and time posted, but will be by 7:00 AM Wednesday February 17th, 2010.

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

Come join forecasters from the UAC along with the talented athletes from Boondockers for our second annual Essential Avy and Riding Skills Workshop. Click here for more details.

Also, we've installed two beacon checkers exclusively for snowmobiler's- one at the Noblett's Trailhead, the other at the Bear River Trailhead. Thanks to Backcountry Access, the Bear River Lodge for donating one of the units and the great folks at the National Weather Service for their partnership, support and hard work making this project happen.Click here for a brief tutorial.


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.