Critical hit with "ray" spells

[Narzul]

When I get a critical hit on a spell like Melf's acid arrow, the damage is doubled 4d4 instead of 2d4.

Now, since this spell has a duration of 1 rnd + 1 rnd/3 level,
I want to know what will be the damage on the following rounds, 4d4 or 2d4 ?

 

[kreynolds]

2d4. Only damage dealt immediately is critical damage. For more info, see Tome & Blood, page 79, second paragraph beneath Critical Hits.

 

[Valmur_Dwur]

2d4, the duration is based on the caster's level not on how he managed to strike the target.

 

[Dr. Zoom]

Yeah, it's 2d4.

 

[kreynolds]

I gotta agree with Dr. Zoom

 

[Crothian]

I'm going to go out on a limb and say that it's 2d4 damage for each additional round.

 

[Narzul]

Thanks all.