One morning this month, after more than 31 inches of snow fell in the previous two days, Utah transportation workers opened a huge garage-type door in a building near a state highway and fired a military howitzer up a mountain in the Salt Lake Valley.
The explosion triggered several avalanches that buried State Route 210 in Little Cottonwood Canyon. In some areas, the snow was 13 feet deep and 150 feet wide. Officials then sent in crews with specialized heavy equipment to clear the two-lane road. They reopened it later that afternoon.
On average, 30 natural and controlled avalanches blanket Route 210 every winter, according to Steven Clark, the Utah Department of Transportation’s avalanche program manager. The agency still relies heavily on howitzers, but is trying to reduce their use, he added. While a round has never fallen short of its target, he noted, the idea is to limit firing rounds in part because of all the people who live and work nearby.
