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 the avalanche danger remains HIGH today on all slopes approaching 35 degrees in steepness, especially those with recent deposits of wind drifted snow. Human triggered avalanches are likely. Today’s avalanches have the possibility of breaking into weak layers of snow near the ground, creating a large, dangerous and possibly unsurvivable slide.

At mid elevations the avalanche danger is CONSIDERABLE on steep wind drifted slopes and human triggered avalanches are probable.

A LOW avalanche danger exists on low angle wind protected slopes, especially those at lower elevations that were void of snow prior to the recent series of storms.

CURRENT CONDITIONS

A brief break in the active weather pattern is on tap this morning. Under mostly cloudy skies temperatures didn’t crater too much overnight, currently they’re in the mid single digits aT both 8,000’ and 10,000’. The strong winds that battered the range yesterday took a brief hiatus around 9:00 last night, though they’re still hummin’ along across the ridges this morning, blowing 15-25 mph, gusting in the 30’s and 40’s near the high peaks. The recent series of storms increased our average upper elevation snow depths to about 3’, but in many places the lack of a supportable base makes for a wallowing, bottomless feel, leading to some tough trail breaking.    

 

 

RECENT ACTIVITY

 

 

It was a very active day around the range with reports of natural avalanches, human triggered avalanches and of course not to be out done, several rogue snowcat triggered avalanches near Nobletts and at Thousand Peaks. The culprit behind all of the activity is the facets both above and below the Thanksgiving raincrust, especially in terrain with a weak, shallow snowpack.  Slides are up to 4' deep.

Thanks to Ted Scroggin, Joe Donnell and Johnny Adolphson for all the great info, pics and awesome observations... you guys rock!

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

 

Westerly winds raged for much of the day yesterday, gusting in the 50’s and 60’s at the upper elevations. Not surprisingly, wind drifts formed along ridges and even in relatively protected mid and lower elevation leeward terrain, overloading our already tender, weak snowpack. While some of those drifts may have settled out a bit overnight, the overall pattern of our fragile snowpack hasn’t changed much at all. If anything the pack is severely stressed by all the additional weight. Terrain that didn’t already avalanche is just waiting for a trigger to come along and tip the scales. In many places the pack will feel strong and good to go, but you have to think about what’s underneath the stout feeling slab. Remember- strong, cohesive snow resting on top of weak sugary snow is a wicked combination. Another curve ball is you can still trigger slides remotely from relatively flat terrain. The harsh reality is this- avalanches triggered today are certain to be large, dangerous and unsurvivable.

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

 

Gusty winds yesterday and again overnight formed slabs on just about every aspect and elevation out there and I think you’ll find wind drifts in unusual locations. Due to the strength of the wind, drifts formed much lower downslope than you might expect. Breakovers, chutes, gullies and sub-ridges should all be approached with caution. Avalanches triggered within the newly drifted snow can easily break into deeper buried weak layers, creating a much bigger and more dangerous slide than you might’ve bargained for.  

MOUNTAIN WEATHER

 

 

Snow is expected to develop later today ahead of Monday’s main event, which looks like another pretty good shot of snow. It’s a warmer, wetter storm and another foot or so is a good bet by Tuesday afternoon. After a frigid day Saturday, today’s high temperatures in the mid 20’s will seem balmy. Westerly winds this morning switch to the southwest and increase later in the day ushering in the next storm system. Look for hourly averages in the 20’s with gusts in the 40’s along the highest ridges. Tonight southwest winds will be howling, blowing in the 40’s and 50’s.  A series of storms keep things fairly active all week.

 

 

 

GENERAL ANNOUNCEMENTS

Remember- your observations help to save other riders lives. So if you see or trigger any avalanches please let me know what your seeing. You can reach me at 801-231-2170 or craig@utahavalanchecenter.org

While it's quiet, now is a great time to schedule a free avalanche awareness class for your group or club. You can reach me at 801-231-2170 or craig@utahavalanchecenter.org for more details.

The information in this advisory expires 24 hours after the date and time posted. I'll update this advisory by 7:00 am on Wednesday Dec. 24, 2008.

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.