Tuesday, January 24, 2012

Risk and Reward in Little Cottonwood Canyon

Date and source of this photo are unknown.  I've had it for years.
If you know either, let me know.
This weekend brought us a reminder of the risks and rewards of skiing in Little Cottonwood Canyon (LCC).  The rewards are obvious.  LCC offers up some of the best deep powder skiing in the world with an abundant natural snowfall averaging over 500" annually, with an average of 17 deep powder days per season (i.e., days with 10" or more of new snow).  Further, the terrain in the canyon is steep and easily accessible, whether it be by lift or human locomotion.

The risks are also obvious.  There are 34 major slide paths on the south side of LCC, most of which intersect the highway.  These paths have been mapped out beautifully by avalanchemapping.org.

Purchase this and other avalanche maps at
As discussed in the Little Cottonwood Canyon SR-210 Transportation Study, this makes the highway of LCC one of the highest avalanche-risk roads in North America.  One of the most problematic stretches of highway is the area surrounding the White Pine and Little Pine slide areas, which lie just below the lower entrance to Snowbird.  

Snow safety personnel in LCC do an unbelievable job at reducing the risk posed by these slide paths.  As noted in the transportation study, "SR-210s great safety record is due to the high level of dedication, training, and collaboration of UDOT, Salt Lake County Sheriff, USFS, and resort and snow safety personnel." 

That being said, the snow safety personnel cannot completely eliminate risk nor can they ensure that the road can be open 24/7 during the ski season.  Closures occur during avalanche control work, the removal of slides that have hit the highway, etc.  This occurred from Saturday night into Sunday, resulting in a log jam at and around the bottom of LCC and a number of frustrated skiers.  

Compounding the challenge is the sheer volume of traffic in LCC during the ski season.  Average daily traffic is ~5,000 vehicles, peaking at 8,000 on high volume days.  It is not uncommon during periods of heavy snowfall for a trip down the canyon at the end of a busy ski day to take more than an hour from Alta.  

The transportation study suggests two avenues for risk reduction, one involving changes to the road and avalanche control.  These involve active measures for avalanche control and passive measures involving structural changes to the road, such as the use of snowsheds, berms, and nets.  The other avenue involves changes in traffic.  

Source: Little Cottonwood Canyon SR-210 Transportation Study
The transportation study includes a discussion of alternatives for the future.  A few minor alternatives have already been implemented, whereas other proposed alternatives have proven highly controversial (e.g., skier compaction enabled by a lift up Flagstaff Peak).  There are many others, such as options for highway realignment or rail.  Have a look for yourself here.


  1. I did a google image search by uploading the ski bus image itself, which led me to this site: http://utahweather.org/UWC/weather_pictures/weather_photos_1900-2002.html

    Their caption is "On December 23, 1988, a cold front produced heavy snow over the Wasatch Front, with up to five inches reported in some valleys, eight inches along the benches, and two to three feet in the mountains. Several avalanches occurred up Little Cottonwood Canyon. This bus was caught in a snowslide at White Pine in Little Cottonwood Canyon. (Photos courtesy of the National Weather Service.)"

  2. Ian - much thanks! I swear you can find the pot of gold at the end of the rainbow with Google. Plus, it's the infamous White Pine slide path yet again.

  3. Important topic. It's worth mentioning that at risk to UDOT's Avalanche Control program are human beings placing themselves within firing range. Usually, the dawn-patrolling skier just isn't aware that control work is occurring that morning, despite signs and other communication. However, it remains a significant concern for the program - the day someone gets hurt or killed during control work will be the end of the program and the start of some of the more controversial control methods. If you dawn patrol in any of the slide paths shown above, find out whether control work will be occurring that day. There are a number of resources, some of which are: @UDOTavy Twitter account, udot.utah.gov/avalanche, (801) 975-4838, UAC page, etc. For visuals, UDOT has created maps (example here: http://www.udot.utah.gov/main/f?p=100:pg:0::::T,V:1672,60997) showing NO GO terrain during control work.

  4. Good point LPJ. Thanks for sharing.