So I was playing Dwarf Fortress, and my dwarfs began randomly bleeding on their way to fetch water, and soon succumbing to their injuries. I tried looking for causes for their death, but I couldn't find any of the obvious culprits. No carp, no goblins, no nothing. I even sent out a small military party to patrol the area from my fortress to the river, and I came up with nothing. After a while, all my dwarfs started to die from dehydration.
An attempt to reclaim the fortress resulted in all of the new immigrants having tantrums for unexplained reasons, and then soon dying as a result.
Does anyone know what the cause of this may be?