My first AVCON roto was the winter of 1970/71 and I lived through that arty slaughter. Went on an NBCW course in Borden right after coming back from AVCON and found my Battery - H Battery - had disappeared and the regiment was half the size it was before I went to AVCON. There were no spare gunners after that - hell, I never saw a battery with more than 80% of the peacetime establishment (except briefly in the mid-Seventies when they stood up air defence)
The first artillery trials there were held in 1959 and the program went online in 1962. It was done in conjunction with a massive construction project of snowsheds on both the highway and the rail line through there. The Trans Canada only opened up in the 1950s. Up until the TCH opened, the pass was mainly a rail route. Rogers Pass was deadly and they had over 200 people had died in the pass. 62 workers alone died when a second avalanche hit them in 1910 while they were digging out a train caught in a prior slide.
If I recall in my talks with the Schleiss brothers back then, artillery was the favoured solution from their point of view because of several factors:
1. guns delivered a consistent result in all weather conditions which you wouldn't be able to do with helicopter dropped explosives or pneumatically delivered ones. Literally, a half mill deviation on some crest triggers would end up with a round flying over the mountain.
2. The 106mm recoilless rifle has a limited range which would not be able to reach many of the slide trigger points and also had elevation limitations to shoot uphill. We did use a 75mm pack howitzer for plinking non-standard targets until the ammo ran out but it was an issue as without brakes and no soil to dig the spade into it would skitter across the frozen road and shoulders every time we fired it.
3. the priority mission was to keep the rail lines open and secondly the road with the least interruptions possible. It's basically a no fail mission. They get 400 inches of snowfall every year and as I mentioned earlier, many of the shoots are in the middle of blizzards. The trick is to get the avalanche triggered early as the snow falls so that the slide never builds enough mass to actually reaches the rail line or the road. I recall one shoot that lasted three full days in a blizzard and we slept in the trucks while they opened the road and rail line for an hour or two now and then to let traffic through.
IMHO using military equipment and ammunition conforms to a military task. The fact that you can train a civilian to do it is beside the fact. I'm not sure I want a bunch of civilians in charge of artillery and high explosive rounds. The CAF does lots of things that are not "military" in nature - flood and fire fighting are just some examples. AVCON is more military than that.
Anyhow - Fun times. We never had problems finding volunteers for it then. (Those were the days when there was a hotel with staff and a heated outdoor pool at the summit)
Here's a little
booklet on it.