Wasatch Cache National Forest
In partnership with: Utah Division of State Parks and Recreation, The Friends of the Utah Avalanche Center, Utah Department of Emergency Services and Homeland Security and Salt Lake County.

keeping you on top


Tuesday, December 18, 2007  7:30 am
Good morning, this is Brett Kobernik with the Forest Service Utah Avalanche Center with your backcountry avalanche and mountain weather advisory.  Today is Tuesday, December 18, 2007 and it’s about 7:30 am.


Current Conditions:

Skies are mostly clear this morning with temperatures again in the low twenties and high teens.  Southwesterly winds picked up somewhat since yesterday afternoon gusting into the 30s and 40s along the higher ridges but speeds are slower at the lower elevations compared to 24 hours ago.


Avalanche Discussion:

Winds from Sunday night did a number to the snow surface at most elevations forming crusts and some fresh drifts.  There were a few reports of some natural avalanche activity from the wind along with a few large cornices releasing naturally in the Deer Valley area.  Control work also produced some results on the Park City side of the range.


Fresh wind crusts and drifts sit on top of lighter density snow that has faceted a bit or become weak in many places.  Aside from needing to pay attention to these drifts today we will want to also consider how they will act with the expected new snow added on top of them.  This could be a bit tricky with the inherently variable nature of wind drifted snow and how it’s changed the snow surface dramatically from place to place.  The snow under these crusts isn’t exceptionally weak but weak enough to demand some attention over the next few days.


We can’t forget about our persistent weakness deeper in the snowpack either.  This is going to get trickier as well as we add more snow to it.  Many northerly facing slopes hold weaker snow near the ground.  This weakness varies greatly from place to place but is most pronounced in the Cottonwoods.  However, the mid portion of the snowpack has gained tremendous strength in many areas over the last week.  This has “bridged” over the weakness making it harder to collapse.  In simple terms, I don’t think this problem is going to be as “in your face” as it has been over the last few weeks.  This is tricky as not every north facing slope is going to collapse or avalanche.  These are conditions that tend to catch experienced people.  I don’t think we’ve seen the last of this buried weakness and would expect some avalanching down to this layer with another significant load.  The sure way to avoid it is to leave the northerly facing slopes alone through this next series of storms and reassess the snowpack afterward.



Bottom Line:

There is a MODERATE avalanche danger in the Ogden, Salt Lake, Park City and Provo area mountains.  Human triggered avalanches are possible.  This includes avalanches from the recent wind events mainly on northwest through southeast facing slopes as well as the chance of triggering a slide into older snow at the upper elevation northerly facing slopes.  The avalanche danger will be on the rise over the next few days.


Mountain Weather: 

We have two systems that will produce snow through Friday.  Today we’ll see increasing clouds with temperatures in the upper 20s at the lower elevations and low 20s along the ridgetops.  Southwesterly winds will continue in the 10 to 20 mph range gusting into the 30s and 40s at the higher elevations.  Snowfall from this first weaker system will mainly be overnight tonight with 4 to 6 inches expected and a bit more possible in the Cottonwoods.  There will be a slight break on Wednesday before a colder and better defined system moves in for Thursday into Friday which should produce another good shot of snow. 



The Wasatch Powderbird Guides will be not be flying today.


For an avalanche education class list, click HERE.  

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

The UAC has temporary job openings for doing avalanche outreach in more rural areas.
  Click HERE for info.

UDOT highway avalanche control work info can be found HERE or by calling (801) 975-4838.

Our statewide tollfree line is 1-888-999-4019 (early morning, option 8).

For our classic text advisory click HERE.

If you’re getting out and see anything we should know about please let us know.  You can leave a message at
(801) 524-5304 or 1-800-662-4140, or email us at [email protected]. (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 advisory by 7:30 Wednesday morning.