a Sig Op said:
Here's a what somthing that's either a silly or sensitive question, but I'm curious...
How would duds be dealt with in avalance control? Or is that an issue?
Duds do occur, but are rare. They use an older but very reliable point detonating fuse to do the job, the M557.
While the targets are generally very near the peaks of the mountains, that doesn't mean any duds would necessarily remain up there. Duds have been known to show up from time to time below the treeline too, getting brought down with the spring thaw or an avalanche itself. Even so, the Park does have very good control measures to steer people away from potential danger areas.
http://www.pc.gc.ca/pn-np/bc/glacier/visit/visit19.aspx
Those hiking/skiing in the area are warned about this at the information centre, and the instruction is quite simple, leave it alone and report it to the nearest Park office. Amongst the visual aids in the Parks Canada office in Rogers pass there's even a picture of an old 4.2" mortar round!
Duds are normally dealt with in situ by a DND EOD team.
While parks Canada actually owns the ammunition, they are supported by DND ammo techs.