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Old 09-27-2016, 07:19 AM   #121
Icelander
 
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Default Some Notes on the Effects of the B O O M - Initial Conditions

At least 2,500 lbs. of finely dusted flour was airborne and hit with 3+ HP of burning damage with the Incendiary modifier during the ignition Fireball; i.e. enough to set on fire clothing and so probably enough to set on fire even hexes where it was somewhat imperfectly clumped. The hexes airborne near the bursting fireball suffered up to 79 HP of burning damage with the Incendiary modifier and probably some 40% of the airborne flour dust was in hexes which suffered 10+ HP of burning damage with the Incendiary modifier, enough to set nearly anything on fire and probably enough to consume fine dust in an insignificant fraction of a second. Some 2,500 lbs.* of finely dusted flour was on the ground, heavily clustered on the road where the air drop was made. Hexes containing it suffered between 15 HP to 2 HP, with 90% of it suffering more than 3 HP burning damage with the Incendiary modifier and 30% suffering more than 10 HP burning damage with the Incendiary modifier. This could mean some secondary explosions and in any event, a lot of burning dust spread around.

The whole 2,000 lbs. of coal dust was perfectly mixed with air within the whirlwind-form body of the djinn, still consciously keeping it around him and mixing it with air when hit. All hexes with coal dust in them suffered 10+ HP of burning damage with the Incendiary modifier from the ignition Fireball and so would have been on fire even if they were only as flammable as flesh or wet wood. As close to 100% near-instant combustion as is possible for this part, with all that implies for a huge fuel-air explosion, not just conflagration.

The entire 4,000 lbs. of chaff (corn husks) and other mill by-products were close enough to the ignition fireball to suffer 3+ HP burning damage with the Incendiary modifier. Even though the chaff is much less flammable than the finer particles of coal dust or flour, the Incendiary modifier means that it was probably all set on fire. Despite the fireball being detonated only 5 seconds after the last bag of it hit the ground from 1,000 yards, only 600 lbs. of the chaff was airborne at the time of ignition, however, as it did not float as well on the controlled winds of the djinn and minor air elementals as the finer dusts. The other 3,400 lbs. of chaff were set on fire on the ground, hopefully sucked into the air to contribute to some secondary conflagrations/explosions and at minimum caused a huge blaze and rained down flaming sparks over a large area.

Around a ton of the dried dung was still falling to the ground when the ignition fireball hit. Another ton had just impacted the ground and some 100 lbs. of it was thrown up as airborne dust, with another 200 lbs. going in all directions as flying chunks, just at the second when the fireball hit. The last ton was lying on the ground in the target area, as battered and spread around as dried dung that has fallen a 1,000 yards and hit the ground in boxes that splintered, amphoras that exploded and kegs that was knocked apart. Some 40% of the dried dung will have suffered 3+ HP of burning damage with the Incendiary modifier, which burns it up in less than a second, and 90% of it suffered 1+ HP of burning damage with the Incendiary modifier, which is plenty enough to ignite it.

*Another 1,000 lbs. of fine flour dust was dropped within a 100 yards from the center of the ignition fireball, with 75% of it suffering at least 1+ HP burning damage with the Incendiary modifier from the ignition, but most of this was indifferently scattered, not in high enough concentrations to trigger a useful conflagration after the magical fireball or lying on the ground around the road. It may give some minor useful secondary effects, being spread around by the main explosion as fiery sparks.
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Last edited by Icelander; 09-27-2016 at 07:35 AM.
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Old 09-27-2016, 07:57 AM   #122
Nereidalbel
 
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Default Re: Dust Explosion - Grain, flour, wheat

Sounds like somebody's army just had a REALLY bad day. How'd everything go after the FWOOSH?
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Old 09-27-2016, 11:55 AM   #123
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Default Re: Dust Explosion - Grain, flour, wheat

Quote:
Originally Posted by Nereidalbel View Post
Sounds like somebody's army just had a REALLY bad day. How'd everything go after the FWOOSH?
Yes! How may enemy troops did it take out, and how's the siege looking now?
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Old 09-27-2016, 12:51 PM   #124
Icelander
 
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Default Re: Dust Explosion - Grain, flour, wheat

Quote:
Originally Posted by Nereidalbel View Post
Sounds like somebody's army just had a REALLY bad day. How'd everything go after the FWOOSH?
Quote:
Originally Posted by Joe View Post
Yes! How may enemy troops did it take out, and how's the siege looking now?
The other PCs actually held the breach and counterattacked. At the moment of the big fireball, they took advantage of a wavering among the enemy to seize the rubble-filled breach and even pursue those units who had been engaged at the walls before falling back. They captured the leader who ordered the assault on the breach, which was an emotional response and not part of the plan of the general who is in overall command (though he had finally moved to reinforce it).

The breach and the area in front of it is filled with dead and wounded. Some 1,500 of the enemy and 400 of the PCs side are lying there. There were a lot of smokepowder grenades slung there, some Alchemist's Fire burnt, a fairly brisk mechanical artillery shower and many, many volleys of musket fire from Marines. And, of course, a lot of arrows and slingshot. Not to mention the 20 minutes of desperate melee.

The immediate effects of the dust explosion blast were to cause the reinforcements marching toward a breach in the walls of Shussel to cease doing so. The light troops and skirmishers mostly broke, even if they may not have suffered all that many casualties, as they consist mainly of former Untheri slaves enlisted in church-owned slave battalions to fight their former masters. One 'Chessentan'* mercenary 'Lotus'** or regiment retreated in fairly good order, with flash burns among several.

One Chessentan mercenary Lotus (regiment) was at the epicenter of the blast. It is effectively destroyed. Perhaps five hundred men would have died immediately, with the rest at least not fighting any time soon.

I actually haven't figured out exactly how big the cloud of fire would have been, how much, if anything, secondary effects are worth and what the effects of sparks raining down would be.

I'd welcome further suggestions. One PC is going to want to go into the fires that remain after the explosion, because he loves fire and because he dropped a magic item worth more than $1,000,000 into them.

*Many in these regiments do indeed have Chessentan ancestors, but about half of the soldiers are born in Mulhorand and some have been living there for three or four generations.
**A Mulhorandi term for a regiment of 1,000 men.
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