Ok, back up! Is this even possible?!
I got word that the human caravan which spent the siege inside my walls had left. Fine, no problems.
Shortly after I heard that one of my dwarves had drowned. Again, it's a nuisance, but it happens from time to time when the lake is refilling.
But then I take a look, and see not one, not two, but THREE dwarves at the bottom of the lake, along with what appears to be the contents of a caravan wagon. The combat report logs are filled with dwarves, humans and horses taking damage from crashing into things, and I have no idea what happened. My first thought was cave-in, but since there's no evidence of this, I'm thinking one of two things:
1. The wagon, with my dwarves walking alongside it, took the wrong route. Instead of going over the bridge, it went across the mouth of the river (which is only 1/7 or 2/7 right now) and got swept down into the lake, taking my dwarves with it. I guess this seems most likely.
2. The "driver" of the wagon somehow lost control, and drove it into the lake, taking my dwarves with it. Not sure if this is even possible.
I'm unsure about scenario #1 though, since water doesn't seem to sweep creatures along when I'm using my tidal wave weapon, so not sure if it would do it here.
Any theories?
EDIT: Dammit, is the "Traffic Area"-system just a suggestion or are my dwarves retarded?! I've set the entire lake to restricted (all z-levels, max cost), and the edges around it to high, but they STILL insist on wading across the damn river mouth. Almost lost four more just now, before I reacted and ordered them all to burrow inside.
EDIT2: Ok, I think I've just about had it with this fortress now. I waited until winter to recover all the bodies and stuff by digging in the ice. Then I noticed that, of course, some of it had ended up in the ONE pocket of water that doesn't freeze. Fine, I think, I'll just dig out the wall and drain it, it's just a 4x4 square. Easier said than done, since the stuff freezes instantly... But the water level DOES drop every time this happens, so, I figure, it's just rinse and repeat! Piece of cake!
End result: I have no miners. They have all gone missing, mysteriously. Someone mentioned that they'd seen an ice wall resembling them, but I don't know... This is the second time in the history of this fortress that I'm out of miners.