Just how predictable is falling damage?

Just how predictable is falling damage?

Falls generally seem like things that ought to be predictably dangerous. We’ve all experienced a bad fall, so we know that they can hurt us. Moreover, a fear of falling has been shown to be one of the very few fears which are probably built right into our DNA; children have to learn to be afraid of dogs or hot objects, but even babies who have just learned to crawl will avoid drop-offs and shy away from optical illusions that make them think there’s no ground below them. The mathematics of falling supports our simple view: if an object in normal Earth gravity has no support, it begins accelerating towards the ground at 9.8 meters per second per second, and when it finally comes into contact with another surface its velocity at that moment predicts the blunt force trauma that the creature sustains. Various factors of our environment place an upper limit to the speed which a falling object can reach, no matter how far or for how long it falls, which we call “terminal velocity” (because it’s the velocity at which acceleration stops, not because it’s the velocity at which a fall becomes terminal). In any event, we all have a pretty good sense that if we jump more than a couple of feet we risk hurting our feet or knees on landing, and if we fall off the roof of a two-storey house we’re going to be in pain, and if we fall off of an office building then the consequences will be severe.

The major SRDs take a very logical and pragmatic approach to falling damage: for every ten feet that a creature falls, they sustain 1d6 points of damage, to a maximum of 20d6, which can be reduced by mid-air acrobatics or by landing on a soft surface. These rules synch up with reality quite well, and arguably do a better job of representing real Earth physics than many other rules do. Granted, the 20d6 damage cap arguably makes falls more survivable than they tend to be in real life, but the average 60 points of damage is still enough to kill most living creatures, and adventurers always tend to follow their own peculiar physical laws in any event.

There are, however, other circumstances in which falls can be much less deadly. The vast majority of people who fall a hundred feet are going to die, but there are verified cases of people falling much, much farther than that and surviving. They may not survive unscathed, but survive they do, and in some cases, survive in good enough physical shape to survive for weeks before accessing medical treatment.

Consider the famous case of Juliane Koepcke, which has been described in detail in several books and films and which I’ll give only an unfairly short summary which leaves out the whole story of what happened after her fall (which is remarkable and worth reading, but not relevant to this discussion). The very, very short version is that as a teenager, Koepcke was in an airplane which began breaking up and, still strapped into her chair, she was thrown into mid-air and fell an estimated ten thousand feet. She survived with only fairly minor injuries, the worst of which was a broken clavicle. A number of explanations have been put forward to explain how Koepcke survived: that the seat she in increased wind resistance enough to function as a sort of parachute, or that the high winds of the storm that destroyed the plane slowed her fall, or that crashing through thick jungle foliage slowed her fall much like the woven layers of Kevlar stop a bullet.

Koepcke isn’t the only example of survivors of falls from extreme height. In 1944, Nicholas Alkemade jumped from a burning military aircraft and fell an estimated eighteen thousand feet; it’s believed that he survived because he landed on a series of pine-tree branches that slowed him enough for the cushion of snow on the ground to be survivable, and he reportedly suffered nothing worse than a sprain. The story of Ivan Chisov a couple of years earlier is quite similar; he is believed to have survived his twenty-thousand-foot drop by virtue of hitting a snow-covered ravine wall at an angle that bled off his speed rather than stopping him instantly. Perhaps because he didn’t have the benefit of a canopy of trees, he suffered multiple major injuries and fractures. Some dozen other similar stories can be found in the medical literature and popular media, and while some of these stories are almost certainly either false or exaggerated, it’s likely that at least one of them is true and that fact alone forces us to question how certain we are that extreme falls are invariably deadly, even if the odds of survival are one in a million or worse.

For obvious reasons, the people who created most RPGs don’t feel obligated to come up with rules for improbably surviving twenty thousand-foot drops, and I couldn’t begin to imagine how I would come up with adequate rules here. What we can conclude is that someone might have a chance of surviving such a fall if their speed is sufficiently reduced before impact. This might happen by hitting sequential tree branches, each of which slows the faller by a tiny amount, or conceivably it might happen by hitting a slanted surface in such a way that the creature scrapes along it for a long distance as opposed to stopping all at once. In many science fiction story, jump-troopers and other long-fallers survive by landing in special gels or other surfaces that absorb the energy of their impacts, and magic, of course, can be used to justify pretty much anything. The bottom line, perhaps, is that very few things in this life are 100% certain, and falling sometimes deals much less damage than 20d6. 

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 June 18, 2016. 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.