The Idiosyncrasies of Exploding

Eric Lis

What is 10d6 damage, exactly? Let's ask people who have survived being caught in a fireball.

Damage is a pretty abstract thing in most role-playing games. In games such as Dungeons & Dragons and Pathfinder, most of the harm sustained by a character is reflected in hit point damage. Ability score damage happens, but it's a good deal rare and it's almost never caused by a plain ol' sword wound or falling rock. Some game systems use more creative means of expressing injury, such as the recently released (and tremendously fun) Atomic Robo Roleplaying Game, which uses the Fate Core System and represents injuries by adding narrative obstacles to a character, but by and large the majority of RPG systems out there just knock a few ticks off of some sort of health bar. The idea of what exactly hit points represent has never been fully developed, and although we tried to make some sense of it in Insults & Injuries, we certainly didn't explain it fully. By all rights, most injuries that a character sustains should result in a wider array of penalties than hit point damage. In no sensible universe should a character be equally effective in combat at one hit point as they are at one hundred, but this is how it works, because we all want 1) simple game mechanics and 2) powerful and effective characters.

Consider an example: the Fireball spell. In Pathfinder, a Fireball deal 1d6 points of damage per caster level to a certain maximum. This can be debilitating or deadly, but it's still just hit point damage. Should that be all it does? Unlike many damage-dealing spells, which can't be easily compared to a real-life mechanism, we have a pretty good idea of what a fireball does to someone in the real world. In fact, in the real world, the problem we have is that different types of explosives create different types of fireballs, which leads to different types of injuries. Here are a few, with some references for your further reading and scheming.

Perhaps the single "purest" sort of explosion in real life is the natural gas explosion. When gas explodes, it results in powerful, fiery explosion without a lot of other stuff mixed in (for examples of "other stuff," keep reading). A gas explosion causes several different forms of injury all at once, due to the heat, the wave of pressure, and then the resulting vacuum as the pressure waves passes. First, there's body-surface burns, which are among the wounds most prone to poor healing, scarring, and infection. Of patients admitted to a special burn unit in Germany over a sixteen year period, about three out of every four require skin grafts or other surgery because natural healing is deemed too unsafe. Many people sustain head trauma, including relatively rare concussions and other severe brain injuries, either from the explosion or from hitting the ground after it. Eye injuries are common, although complete vision loss is rare. Many people suffer temporary hearing damage, but no cases in this report had permanent hearing loss. About a quarter of victims sustain abdominal trauma, but abdominal organ injury is rare. No victims in this case series sustained important fractures. The deadliest injury was inhalation injury. Inhalation of burning air and other particles can damage the lung lining which allows gasses to pass into and out of the blood. About one in five people sustained inhalation injury in this series and about one in twenty required invasive care. Mortality was about one in five (or two out of three of those with inhalation injury) which, assuming these were mostly commoners, means the explosion probably dealt much less than 60 points of damage. Of course, this mortality rate is with modern specialized medical care; the mortality rate of an untreated creature would be much worse.

Let's look at another kind of explosion: gunpowder explosion. Gunpowder is seen in many campaign settings and is frequently used to make bombs. Today, China has great expertise in treating gunpowder explosions, due to their cultural heritage of setting off fireworks for both fun and murder. Gunpowder burns are often deadlier than other burns because they burn at an extremely high temperature, which can result in extremely large and deep wounds, and in this series, they tended to occur in confined areas as opposed to in the open. Many of the patients had the same heat-related inhalation injuries as in other explosions, with significant charring of the airways, but worsened because the gunpowder produced a great deal of soot, which settles into the respiratory tract. With proper medical care, half of the deaths reported in this case series occurred more than one week after the actual explosion, mainly due to infection and multi-organ failure.

Then we have battlefield explosions. In modern warfare as well as many role-playing games, a significant number of explosions are the result of mines and ranged explosive weapons, resulting in certain body parts (hands, feet, and head) being more likely to be burned. Initial burns tended to be exacerbated by exposure to nearby and newly-burning objects, including one's own clothing. Although burn size tends to be relatively small, weapon explosions are complicated by shrapnel, especially in the case of suicide bombers with small but metal-packed explosives. Victims of suicide bombs suffer much less burn damage but much more internal injury, open (and uncauterized) wounds, and injuries to nerves and blood vessels. In at least one case, victims who survived the initial explosion were also exposed to hepatitis B due to infectious bone fragments from the bomber that got lodged in their bodies (think about that the next time your players face off against the exploding zombies that seem to appear in every monster manual these days). A certain number of injuries are also missed when healers who examine the victim, because small penetration wounds bay be concealed by clothes or hair the way a large burn can't be.

Needless to say, there are many other types of explosions, all of which cause slightly different forms of harm. Meth lab explosions differ from burns due to overly hot food. The world is truly filled with an endless variety of things that can hurt you in their own unique, special way.

So that's real life. Is any of it relevant to a Fireball spell? A magical fireball is a bit different from one in real life. A magic fireball is basically just a spontaneous release of heat and fire. As such, it might be reasonable to say that it doesn't cause the same chemical injuries as a gunpowder or drug-lab explosion. A fireball also doesn't release shrapnel, so the character hit by one doesn't sustain the same harm from foreign bodies. Lastly, the rules explicitly state that the fireball creates no differential of pressure -- which doesn't seem physically possible, but there you go -- so the target doesn't have the same risk of ear and lung damage. A magical fireball may not have much in common with any sort of real explosion, but it certainly carries its own special risks and side-effects, just as every type of explosion is subtly (or not so subtly) different from others. Next time you roll hit point damage, consider what, precisely, is causing the harm, and whether it really is as simple as it looks. 

More than four years ago, Dr. Eris Lis, M.D., began writing a series of brilliant and informative posts on RPGs through the eyes of a medical professional, and this is the one that appeared here on August 24, 2014. Lis is a physician, gamer, and author of the Skirmisher Publishing LLC OGL sourcebook Insults & Injuries, which is also available for the Pathfinder RPG system