Avalanche Control with AvalauncherPosted: December 15, 2008
Here are some photos from a shoot we did with one of our avalauncher guns in March of 2007. Sure, it’s not really relevant with what’s going on currently at the Lake, as we have yet to fire any of the guns this season, but on a day where the temperatures are forcing closures of most lifts and most sane people are staying home, I say anything goes!
Back on March 26, 2007, it was decided to control an area called Exit of Purple Bowl, located on Wolverine Ridge which is the ridge to the north of the Larch area, and separates Larch from the Wolverine Valley and Mt. Redoubt. The targeted area is outside the operational boundary of the resort, but because it has the potential to avalanche into in-bounds terrain (lowest part of Rock Garden) , it receives control nonetheless. This area is also where anyone coming out of Purple Bowl passes through before re-entering the resort boundary.
The avalauncher is a compressed-gas-powered gun that fires explosive projectiles onto slopes too distant or dangerous for patrollers to approach on skis. Shoots either take place at the start or end of the day, making it easier to ensure no people are anywhere near the targeted areas. The explosives look like mini rockets, with plastic nose cones and tail fin assemblies to provide good flight characteristics. The guns each have a laminated photograph of the surrounding terrain, showing required pressures and barrel elevations for each desired shot placement. Since these bombs are light and follow a ballistic trajectory, they can be affected by wind, so the gunner must take that into account by altering pressure and barrel direction.
Like any explosive use, resuts vary, but I was able to get some shots of one good avalanche we got to go, and clearly shows the progression of the sliding snow:
Avalauncher shoots make up only a small part of a season’s avalanche control, and it’s possible for one or more guns to go a whole season without being fired. It’s one of the more exciting methods of avalanche control, possibly ranking only behind heli-bombing (and maybe artillery shells, but we don’t have those at the Lake!).