Avalanche Control with Avalauncher

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.

Patrollers ready the avalauncher for a morning shoot.

Patrollers ready the avalauncher for a morning shoot.

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:

Explosive detonates upon impact.

Explosive detonates on impact.

Fracture lines begin to appear.

Fracture lines begin to appear.

Fracture lines grow, snow begins to slide.

Snow begins to slide.

Snow is sliding, new fracture lines appear below.

New fracture lines appear.

Avalanche gets bigger with additional area sliding.

Avalanche gets bigger with additional area sliding.

Further down, the avalanche covers previous day's ski tracks.

Further down, the avalanche covers previous day's ski tracks.

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!).

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5 Comments on “Avalanche Control with Avalauncher”

  1. Graeme says:

    Great post, have those guns always been avalaunchers? I remember 10 or so years ago watching a shoot from the same gun on Larch and I thought it was an old howitzer cannon or something, but I didn’t get an up close look.

    One question, since this shoot was onto the return from Purple Bowl, how does patrol make sure there isn’t anyone coming back that way? I assume it’s first thing in the morning so someone has been watching for people walking up that way, or maybe there wasn’t even a bootpack set above the lift. Just curious.

    Really been enjoying the site, I’ve been skiing at Louise since I was about 5 or so (27 now) and I’ve learned so much from all your posts. Hopefully it warms up soon and some more snow falls.

    • lakelouiselowdown says:

      The guns at Lake Louise have always been avalaunchers, and I don’t believe that Howitzers have ever been used in Banff National Park. I had the chance to see a Howitzer in use for avalanche control at Snowbird, Utah a few years ago, and it took a crew of four to operate. It was very loud, and the shoot would take place early in the morning in the dark, before anybody was on the mountain.

      As for the Purple Bowl shoot, you’re right – it was first thing in the morning, and while we sometimes get started before Larch chair opens, we’ll always post a patroller at the top of the chair to make sure nobody starts the hike up until the shoot is done.

  2. DanielForrest says:

    Hi,

    I am curious what the effective range of the Avalauncher is. How it is aimed, and if the are currently being manufactured and sold by a company, or are these made in house.?

    • lakelouiselowdown says:

      I think the avalauncher can fire about 1-1.5 km, though at Lake Louise these distances aren’t needed. There are a few manufacturers, so I’m not sure who we got ours from. SEAR Search and Rescue Equipment Canada currently sells the guns and projectiles.

      The aim of the gun is produced by a combination of three things – azimuth (compass) direction, barrel elevation, and gas pressure. The gun is like a big compass – it can swing to point in any desired direction, the barrel can be raised or lowered, and the pressure of the gas increased or decreased. Each gun has a shot placement chart, showing a photo of the terrain in question and all of the normal shot placements on that slope. Each placement will show the bearing, elevation, and pressure values, which can be altered to account for high wind. The value are derived from years of shooting and seeing what works. The shots aren’t always on target, but it’s still the bets way to control slopes too distant or unsafe to approach on foot.

  3. Mooch says:

    That’s really interesting stuff. I bet you love your job. You get to ski at a world class resort, blow stuff up, and help keep people safe. Livin the dream!!! lol!!!


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