@AprilDawn: Your cheerful use of your simworld's natural disaster, working it into your story, is encouraging/inspiring! And thanks for the tip about played ghosts asking the wishing well for their lives back--I didn't know they could do that! Seems more fun than making ambrosia/using a lifebook.
I so wish I'd thought to capture a video of my game's winter massacre (esp. my sim being forced to edge of the pool & stripping), or pictures at least. I was completely concentrated on trying to rescue sims, & didn't think about reporting it here until afterwards.
For those who think it takes mods, or player action, to start a massacre, that was not the case in my game. Don Lothario keeled over all on his own; I didn't even know he'd died until my destined-for-death newlywed sim climbed out of the pool on his own and went to mourn, and the massacre began.
I don't use mods, but I do use testingcheats, including the unofficial ones TwistedMexi found. Could the massacres occur more often in games exposed to testingcheats? We know they nerfed the cheats; maybe that's one of the reasons why?
(edited to remove a bolding error)