Idaho Avalanche Buries State Highway 21 Under 60 Feet of Snow

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By: By Jon Erdman

Published: March 13,2014

 

 

 

 

 

 

Snow, trees, and other debris cover Idaho state highway 21 northeast of Boise on Mar. 11, 2014. An ITD maintenance foreman, wearing orange, is standing on the debris pile. (Idaho Transportation Department)

   An Idaho state highway that was buried in an avalanche last week may be closed indefinitely.
The avalanche danger kept investigators away from the site until earlier this week, when an Idaho Transportation Department (ITD) took a closer look. The crew reports the avalanche along State Highway 21 in Canyon Creek, northeast of Boise, was 50-60 feet deep and covering a 300-500 foot section of the road.
The photo above gives you a better idea about how large the snow and debris pile spread. The orange spot you see on the snow is actually ITD maintenance foreman Stuart Wilson.
The avalanche danger has subsided enough to allow ITD crews to begin a lengthy cleanup. According to the ITD Facebook page, one crew is first working to remove several smaller avalanches on the north side of the slide area near Stanley before they can even get to the largest avalanche mentioned above. A second ITD crew is starting near the town of Lowman.
Due to the challenge of this cleanup, no estimate was given regarding a reopening of the road.
First, the avalanche occurred in a narrow canyon, with limited space to store debris and equipment. Secondly, the debris pile is so tall, an excavator cannot reach the top of it. That means ITD crews will have to bulldoze debris toward each end of the slide area for removal.
Unlike a massive Alaskan avalanche in late January 2014, this slide is not blocking the flow of Canyon Creek, which is running under the piles of debris.

View of avalanche chutes northeast of Lowman, Idaho on March 11, 2014. (Idaho Transportation Department)

• ENLARGE PHOTO

Tree decay from a wildfire 10 years ago was thought to be a factor in the magnitude of this avalanche. The ITD said these decayed trees are no longer able to hold snow on the slope.
According to a story from Boise State Public Radio, there are 54 separate avalanche chutes in the mountains on either side of this segment of State Highway 21 dubbed "avalanche alley." This problematic stretch of road has only been open in winter over the past, roughly, 30 years.
While precipitation since October 1 has only ranged from 47-65 percent of average in the mountains of central Idaho, recent heavy, wet snow loaded on top of older, weaker snow layers lead to the enhanced avalanche danger in early March.
As of March 11, 23 have been killed in avalanches in the winter of 2013-14, according to avalanche.org.

MORE: Career as an Avalanche Forecaster

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An avalanche dog and trainees search for people buried in the snow, on December 11, 2012, during an avalanche dogs training session near Les Deux Alpes ski resort in the French Alps. (JEAN-PIERRE CLATOT/AFP/Getty Images)