quantity-based Weakness?

[Plane]

B161 defines Weakness as a dice of damage per unit of time when exposed to a substance. B262 includes "Weakness: Water" for Body of Fire, as an example.

Is there some rule somewhere on how quantity might matter? It seems like falling into a 1-inch puddle would be just as damaging as falling into a 10ft-deep lake.

In the case of Body of Fire, it might be explained away through their Burning Aura vaporizing water so that it can't continue to damage them, but I don't know what solution to use in the case of those without auras to damage their weakness-inducing substance.

Vampires (also B262) only have a Weakness to sunlight, "Running Water" is merely a Dread but if you made a variant who had Weakness : Running Water too, and wanted wading through a deep raging river to do more damage than walking through a light sparse rain, how would you change Weakness to get that?

[Anthony]

Quantity affects rarity; water drops are more common than lakes. There isn't a rule for scaling the effects, though.

[Mark Skarr]

Originally Posted by Plane

Vampires (also B262) only have a Weakness to sunlight, "Running Water" is merely a Dread but if you made a variant who had Weakness : Running Water too, and wanted wading through a deep raging river to do more damage than walking through a light sparse rain, how would you change Weakness to get that?

That seems to be a setting/game switch. I would set that as an expectation to the players during session zero.

"Your weakness is for a set amount of water. For instance, a normal river. That does the listed damage. Lesser amounts, like a small stream, will inflict less, and greater amounts will inflict more. Until you get the hang of it, I'll be more clear about any time you would take damage from the environment. Don't hesitate to ask in case I forget to give you the information."