Some Fire Magic Questions

[Wendigo]

Turin said:
put up 25 domes of arcane warding+30? repeat every 30 turns.

The chance of a spell going through 30 arcane domes is the same as the chance of going through one: 50%
Domes of the same type do not acumulate effects, different domes do acumulate however (I had once a couple of astral domes on my capitol & was getting blasted with roughly half the spells, instead of the expected 1/4th).

Another small note on what was previously said:
The damage from FFTS is indeed hp based as Cherry said, so it works better vs human sized critters than big ones like Jotuns.
Unlike Murdering winter however, I recall that the damage from FFTS is not affected by the temperature of the province, you will get the same results in cold provinces as in hot ones (easy test: take 100 longdead & blast them in different prov).