Controlled Avalanches

I recently ran across this article in Yahoo News about the serious problems that Colorado has been having with avalanches crossing over highways. Several vehicles have even been knocked off the road and carried hundreds of feet. The article starts off with this attention-grabbing statement:

Crews fired artillery shells Sunday to safely trigger avalanches before they could pose a threat to traffic on a mountain highway...

I was struck (sorry, I just had to put it that way) with the cleverness and the directness of this approach. Although I had never heard of it, I figured this idea had been around for awhile. A Google search amply proved that, but I was floored by this claim that there are over 100K explosions per year just for triggering avalanches, in the Western U.S. alone.

Perhaps you half-remember, as I do, various action movies where the heroes or villains deliberately trigger an avalanche by making a loud sound, such as a gunshot. Apparently that is yet another myth, or at least an exaggeration. In almost every case, the avalanche is triggered by a direct force, such as the weight of a person or the concussion of an explosion. According to the page I mentioned above, the preferred triggering technique is for a skier to approach the area from above, light a dynamite stick with a two-minute fuse, heave it down onto the potential avalanche site, and then ski like crazy to get away. If it is too difficult to get to the area from above, the other approach is to fire at the area from a distance with heavy artillery, as was done in Colorado.

I still think it's pretty cheeky to refer to these as 'controlled avalanches', though. It makes it sound like an overly confident military policy of some sort.