Uintas Avalanche Advisory

Forecaster: Grant Helgeson

SPECIAL ANNOUNCEMENT

Come join forecasters from the UAC along with the talented athletes from Boondockers for our second annual Essential Avy and Riding Skills Workshop.There are a a few open slots left. Click here for more details.


BOTTOM LINE

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


Danger Rose Tutorial

In steep, rocky, mid and upper elevation terrain the stability pattern is complicated and there are pockets of CONSIDERABLE (Level 3) avalanche danger on slopes that face northwest through southeast, particularly those with a shallow snowpack. Dangerous human triggered slides which break into weak snow near the ground are probable in this type of terrain.

On steep, upper elevation slopes with recent deposits of wind drifted snow, the avalanche danger is generally MODERATE and human triggered avalanches are possible.

Low elevation terrain and most sun exposed slopes have a LOW avalanche danger.


CURRENT CONDITIONS

10,000' temps are in the single digits while temperatures at 8,000' hover in the mid teens. Winds are light out of the SW. Yesterday's sun was enough to create a thin melt freeze crust on slopes that face South & West. Riding conditions remain quite good on the shady side of the mountains and there are plenty of meadows still waiting to see a track.


RECENT ACTIVITY

Yesterday I observed a soft slab avalanche triggered by a partial cornice failure on the South face of Baldy.

Friday, a snowmobiler triggered a hard slab avalanche while side-hilling a steep slope in Super Bowl, but fortunately wasn’t caught. The avalanche was 3’ feet deep, 250’ wide, running about 300’ vertically. This slide occurred on a northeast facing slope at around 10,000’ in elevation. Thanks to Harry for the great observation and photos. Please keep ‘em coming!

Click here for more snowpack, weather and avalanche observations.


THREAT #1

WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

The range is a tale of two snowpacks. Where the snowpack is deep, say four feet or greater, we’re seeing the snow gain strength and it’s becoming more difficult to trigger a deep slab avalanche. However, we trigger deep scary avalanches where the pack is thin and weak, say three feet deep or less. Our nemesis, the mid pack facets and weak sugary depth hoar near the ground have gained little strength. It is still possible to trigger slides which initiate in the mid pack and then step down to the ground, as evidenced by Friday’s Super Bowl slide.

We talk a lot about shallow snowpack’s, but you don’t have to be a snow scientist to determine where the pack is shallow. Just take a look around your favorite bowl or chute. If there are rocks, small trees or bushes poking through the snow where they are usually covered up by this time of year, then you're looking at a shallow portion of the snowpack. These are the places where you could still trigger an unmanageable avalanche which breaks into weak snow near the ground. Making matters even trickier is the snow has just enough strength to let you get well out onto the slab before it fails, resulting in a dangerous slide that breaks above you.


THREAT #2

WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

Overnight winds were relatively mild at our Wx stations, but, the Uintas are a very big place, and I never doubt their ability to create localized winds. You're likely to find a tired old wind slab at upper elevations that face N, NE, E & SE. These manageable wind slabs will be less sensitive today so long as we give them proper respect. Avoid putting yourself in a situation where a failing wind slab will make or break your day; like side hilling above a rock band or being in the bottom of a gulley.


MOUNTAIN WEATHER

Today will be on the chilly side as daytime temps top out near 15 F. Light to Moderate snowfall will continue throughout the day, total accumulations as high as 6" are possible. Clearing gives way to high pressure early next week before a chance of snow from a weak disturbance comes into play midweek.


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 February 24th, 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.