This came up last game, and I realized I had no idea what the rules for falling are in the game. I made something up on the spot. But, I am sure there are some official rules somewhere. Would anyone know the book and page number?

It's in the tome of adventure I believe (don't have it to reference). It's just a small section about environmental damage, from falling to drowning, to fire etc... Basically set the challenge dice based on the distance of the fall and for every challenge they take damage.

It's page 23 that has the suggested complications and tests, along with advice to use progress trackers or other ways of representing such risks not just a "roll or die" test.

I'm pretty sure there is no hard and fast rule.

I've used a challenge die per 10' - failures = wounds, banes = fatigue, chaos = wound becomes a critical wound.