In keeping with my philosophy that you get more damage when you let physics do the heavy lifting:
In Memoriam Bakehouse CrHe(Ig) 25
R: Sight, T: Room, D Momentary
The target room is filled with a cloud of fine, dry flour and some sparks. The resulting powder explosion will do +15 fire damage and +20 blast damage to anyone in the room, +10 fire and blast to anyone in the building that the fireball reaches, +5 fire to anyone outside that it reaches and will blow out walls and ceiling of the room unless heavily built stone thus causing at least partial collapse of the building. Since the explosion is a secondary effect, parma does not help.
Base 3 (processed plant product (could be 2 if pollen was used instead but the inventor did not think of it)), +3 sight, +2 room, +1 ignem requisite.
If you want to be really efficient the use pollen instead of flour and split the spell into a level 15 CrHe and a level 15 CrIg that you fast cast. There have been flour explosions in mills and bakeries since the invention of flour.
No-one will dispute you on explosive flour irl , but havent we gone through this before?
Base 10 for +15 damage in the Creo Ignem Guidelines (page 140) , so ok comparison-wise.
Base 10 for +10 damage in an unnatural shape.
Are there any spells in the RAW , that allow secondary and tertiary damage effects as you describe here?
Magically created oil set on fire doesn't hurt so why should magically created flour? What is the Aristotilian explanation for a flour explosion? What is the medium that is carrying the damage. That's the problem with trying to rely on physics to solve magical problems in Ars Magica it asks as many questions that it answers.
I was sure it did - we recently had a thread about it.
Anyway, I guess the explanation is that the first few flour particles set alight light their neighbors and so on so rapidly that the heat and flame and smoke cannot escape without smashing everything in their path. Or maybe there is a daemon of kaboom reliably summoned by carelessly deployed flour, soot or coal dust near an open flame. It doesn't really matter - my point at the bottom was that it was a known phenomenon and a magus willing to put up with some burns playing with powdered fuel and a candle (or who talked to someone who had) would find out how easy it is to recreate. You can't just scream Aristotlean physics and expect people to have been stupid and blind.
Being directly hit by the "inside" of the explosion should be up against Parma yes, but the medium causing damage then is the surrounding air and any items that gets "moved around" by the original explosion.
And noone could care less about an Aristotelian explanation, as its a well known occurence since before his time.
The Ignem requisite means you can let the spell include ignition all over the whole cloud, not a problem.
However, the flour really needs to be perfectly spread for it to work properly. So i would say add 2 magnitudes for complexity to achieve that perfect spread(and equally perfect ignition all over at the same time) and i think its acceptable. You´re still getting a VERY big BOOM for the size of the spell.
Reviewing that thread it hadn't seemed to be settled. I go with the Magic fuel makes for magical flames school of thought.
I have no problem with it being a kwown phenomenon nor was I arguing its reproducibility in the game. Though your spell seams to create a primary dust explosion which is more dangerous to the room itself then the people or objects in the room. The secondary explosion is generally much scarier to people. It's a bit more like a firestorm then an explosion though caused when large piles of dust are kicked up by the pressure wave and ignited in a slower burning but but hotter tidal waves of fire. Or at least that is what you have to worry about with the coal dust. Training videos can be cool .
I didn't scream anything I had a legitimate question about what medium is carrying the force of the explosion and how it interacts with MR. In Aristotelian physics there is no such thing as inertia. Objects in motion don't stay in motion for the same reasons they do in the real world and there is a good chance an explosion caused by a magically created combustible would roll right over you like a spring breeze if the effect couldn't penetrate your MR.
Sorry about the word scream - that was more a reaction to the first reply and especially the bright blue fixed-your-post. I'm not positing some non-aristotelian mundane medium insulating the burning flour from the parma, I was just making the assumption that burning magical fuel makes mundane fire. If we go with your assumption then yes a mage who resists is unharmed (and in a deoxygenated room with a falling roof )
You could but a few sparks is all you need
I don't think a perfectly even distribution is a problem - Creo is the art of perfection. Having the spell specify the right density of flour in a variable, unseen volume rather than the mass is unusual and could be tricky enough to require a magnitude. And knowing the density to specify is going to need some potentially dangerous non-magical experimentation on behalf of the first inventor and anyone who wants to use a different fuel. Finally a use for natural philosophy.
Ironically, I thought of this spell for an anti-sniper role (like the US marines use thermobaric grenades) but in a close packed, flammable medieval town it's too destructive.
Creo Room is illegal. Creo Ind would create a single perfect mass. To get a perfect distribution, you will need Group. That would also solve the illegal Room Target. 10 cubic paces of flour should be enough to fill the room properly.
A level 4 CrIg does +5 damage, x4 for immersion gives +20. That makes your base 3 acceptable, but the secondary damage seems excessive for a pure Creo spell. If you would Rego natural flour into place or just CrAu, it would remove my "magic object have magically limited damage potential" objection.
You are quite right. And without T: room one would nearly always need an Intellego spell to place the effect. OTOH ten cubic paces of flour is ~5tons so using the T:group version in the field we have a new army killer spell :mrgreen:
I don't think "magic object have magically limited damage potential" is a valid or appropriate objection in ArM5. It's not a strictly balanced effects based system like Hero where what you can do is limited by how useful it is. In the correct circumstances a pound of flour is far more hazardous than a pound of tapioca and those cicumstances are relatively easy to set up - that's life.
Well, there's Last Flight of the Phoenix, HoH-S p 37. It uses a CrIg Base 40 (do +45 damage) and +2 Size to enlarge the effect, and causes decreasing damage to targets that are further away from the target, +20 and +5 in concentric rings. Of course, when you stack +2 Size on top of a lvl 40 base, you can expect some increased damage