Wasatch Cache National Forest

In partnership with: The Friends of the Utah Avalanche Center, Utah Department of Public Safety Division of Comprehensive Emergency Management,

Salt Lake County, and Utah State Parks:


For photos of avalanches and avalanche activity, visit:  http://www.avalanche.org/%7Euac/photos_03-04.htm      (Updated 3/25)

Photos sent in by observers throughout the season visit:  http://www.avalanche.org/~uac/obphotos/observer.html      (Updated 4/2)

For a list of backcountry avalanche activity, visit:  http://www.avalanche.org/%7Euac/Avalanche_List.htm     (Updated 3/31)



Monday, May 03, 2004  2:00 pm


Hello, this is the Forest Service Utah Avalanche Center and we have quit issuing avalanche advisories for the season. 


This does not mean the end of avalanches for the year.  It just means that the money has run out and all of our staff is off doing other things for the summer.  So you’re on your own.  Here’s a few rules of thumb on what spring usually brings in the avalanche department.  


First, as you may imagine, we have to worry about wet avalanches.  The name of the game in spring is to get out early and get off the snow early.  In other words, if you’re sinking in past your ankles then it’s time to head to a more shady slope or head home.  The worst wet slides tend to happen on snowpack that are going through the transition from a cold, dry snowpack to a wet one.  As melt water percolates down through the layers, they can saturate fine grained layers of snow like a sponge or they can pool up above ice crusts.  Then the snow becomes saturated it can very quickly turn into margaritaville and slurp on down the mountain like a thousand concrete trucks dumping their load at once.  But the good news is that after melt water has percolated through a snowpack for just a few days, it dissolves all the layers and all the snow becomes larger grained, very porous and very stable.  As spring progresses, usually the south facing slopes become stable first, then in mid spring, the east and west facing slopes. Then in late spring, the upper elevations north facing slopes are the last ones to go through a wet slide cycle and then become very stable.   You should especially watch out for one or more nights where the snowpack does not refreeze.  So how do you judge that from town?  First you get on the Internet and check out the automated weather stations.  Snowbird has the only mountain stations still working in spring.  Also, be sure to check the date and time because sometimes the weather stations are not working or sometimes the computer servers are down for some reason.


Snowbird Gad Valley graph (9,800’)     

Snowbird Gad Valley table (9,800’)

Snowbird Hidden Peak graph (11,000’)

Snowbird Hidden Peak table (11,000’)


Snow surface temperature depends on both air temperature and on cloud cover.  Snow is a very efficient radiator of heat and with a clear sky, the snow surface can radiate a tremendous about of heat away.  Even with an air temperature in the upper 30’s the snow surface can still refreeze with a clear sky and low humidity.  With cloud cover, though, the air temperature has to be below freezing.   Also, in spring we have to watch out for steep, rock slabs because it’s common for them to produce what we call “glide” avalanches, meaning that the entire snowpack slides slowly down the rock slabs kind of like a glacier until it releases catastrophically at random times.  These tend to occur after several days of very warm temperatures but they can occur randomly too and even with a frozen snow surface.  So watch out for places like Stairs Gulch and Broads Fork, which are notorious areas for glide avalanches.


Finally, you will need to watch out for the usual round of new snow avalanches and wind slabs every time we get a spring snowstorm.  As always, avoid any steep slope with recent deposits of wind drifted snow and you should jump on several small test slopes as you travel to test how well the new snow is bonded to the underlying snow.  And when the new snow gets wet for the first time, it almost always produces damp to wet sluffs on steep slopes.


Well, that’s the basics. 


I should be done with our annual report by about mid May and I will post it on our web site if you’re interested.  Also, if you want a hard copy, just leave a message at 524-5304, 1 800-662-4140, drop us an email at [email protected], or a fax to 524-6301. 


Thanks for a great season and we’ll be talking with you again next fall.

The information in this advisory is from the US Forest Service, which is solely responsible for its content.  This advisory describes general avalanche conditions and local variations always occur.