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Another scary scenario:

Let's say you're in a situation where you have to jump off of a cliff into the water to survive.

The cliff is at least 100 feet high.

What would be the best way to survive the fall and ensure that you don't break a thousand bones when landing in the water?

Dive head first and break water with hands? Cannonball? Or do a pencil drop and break water with feet?

Seems like any one of these would end up hurting quite a bit and might compromise being able to swim away afterwards.

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    I'll bet anything you have that you won't break a thousand bones. 210, tops. – Toby Speight Feb 18 at 9:19
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    Make sure the water is deep enough first? If you don't know that, it's a diceroll no matter what. – J... Feb 18 at 15:45
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    @Hermann: It would definitely help if the water was frozen, but otherwise I'm not so sure. – Michael Seifert Feb 18 at 16:32
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    @TobySpeight You might start the impact with that many bones, sure. But during the course of the impact, the number of independent pieces of bone in your body could increase dramatically. – Graham Feb 18 at 18:37
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    @TobySpeight Did you land right on top of the 4-5 previous jumpers? – Forward Ed Feb 18 at 21:47
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There's an abandoned quarry near me where local kids used to jump off the topmost cliff edge, 100 feet up, every summer. When done properly it is survivable without injury.

You have to break the surface tension with a part of your body that can take the blow, and you have to keep all your muscles clenched and your body absolutely rigid, and you have to hit absolutely perpendicular to the surface.

If you do it wrong, you are likely to be knocked unconscious and drowned.

I do it head first, which means keeping the hands locked together in a double fist, elbows and shoulders locked and rigid, hands directly between the top of head and the water, spine absolutely straight. Do not bend your neck to try to look at the water!

If your arms are not locked and rigid your fists will hit your head and knock you unconscious or your arms will be ripped back and dislocated and the water will knock you unconscious.

It can also be done feet first, which means keeping the knees locked, all muscles in legs, thighs and butt absolutely clenched rigid, heels sharply pointed down, looking straight ahead and hitting the water again perpendicular to the surface.

If your feet spread you will crush your genitalia, and if you're male will require medical treatment. If you do not clench your butt you may intake water with damaging force. If you look down you will get smacked in the face hard enough to break your nose and possibly knock you out.

I did it wrong once, and hit at an angle instead of perpendicular. Striking the water felt like hitting concrete. My left arm was ripped backwards, completely dislocating the shoulder. I was knocked unconscious and concussed. The rapid compression of my chest ruptured my left lung and my legs were temporarily paralyzed, perhaps by the impact to my spine or skull. Although I survived, my body was permanently damaged by the injury - my left shoulder dislocates more easily than my right, and I have a scar tissue mass in my lung from the haemothorax.

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    ouch. this should probably be the accepted answer. i am not surprised you have to be very specific in how you land, which is why i didn't go into position much beyond my choice of feet first, always. where are your arms if you are feet first? at your side? above your head? i get the impression that from extreme heights you can't do any tricks to minimize how deep you go. – Italian Philosophers 4 Monica Feb 18 at 23:00
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    my left shoulder dislocates more easily than my right :-o FWIW, my father used to tell stories about jumping off bridges in New York city when he was young. Apparently holding a blanket or sheet in both hands over your head helps to ensure a vertical, feet-first entry into the water. Even a shirt would probably help some. – Andrew Henle Feb 19 at 16:21
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    @StephenMIrving head first or feet first if you hit rocks from that far up your spine is a goner and there's very little that can be done to save you. If you aren't sure of a clear landing zone, don't jump it's not worth the risk – BKlassen Feb 19 at 18:37
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    @ItalianPhilosophers4Monica from my own experience as a lifeguard and swim instructor, it's easier to flatten out your entry going feet first than head first. Feet first once you're in the water you can push your feet out parallel to the water surface to limit your depth – BKlassen Feb 19 at 18:45
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    In one of your comments you mention "surface tension", but the property of water that changes upon the splash is actually rather "compressibility". It is because a whirlwind of water and light, soft air bubbles is easier to displace than unbroken incompressible water. If surface tension was also a factor, you'd notice differences between going in wet, dry, and waxed (wet skin would make immersion easier, and dry or waxed skin would make walking on water easier). – Jirka Hanika Feb 20 at 15:00
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Feet first is always best - you might break your legs if you hit the bottom, but at least you won't break your back, neck, or be knocked unconscious - all of which can kill you, either through the damage to the spine or through drowning.

I would aim to jump in angled away from the cliff (i.e. body not totally vertical), arms across chest or covering mouth/nose (not holding nose - you'll break your nose when the water shoves your arm), and aim to use the momentum of the jump to cause me to swing rapidly under the water dissipating the momentum, so as to not go too deep. See rather crude drawing I just whipped up:

Exaggerated jumping image

Basically the jump should look like the out-of-helicopter jumps that you might see the Coast-guard do, such as the one in the linked Youtube video.

Edited to add: there's some physics on the jump here, and within that the top answer indicates that they were trained to survive a fall from 100 ft (30 metre; aircraft carrier height), not that they had to do it. Other answers indicate that the max survivable seems to be about 250 feet (75 metre) into water.

Also edited to add: It's not as easy as you might think - in my experience, if you do it right, making yourself as hydrodynamic as possible, a simple jump off the side of a pool (~ 1 ft / 30 cm) into the water can get you to the bottom of a dive pool (~20 ft / 6 metre) pretty handily, so there's a real risk of breaking bones jumping from any substantial height into water, even if it is quite deep.

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    That helicopter jump is only about 5m (15') based on the fact they're falling for roughly 1 second. It may still be a good model, but they're also wearing fins which may affect how they have to hold their feet, and also means they won't go as deep – Chris H Feb 18 at 9:01
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    Yes, but the basic jump will be very similar in terms of jumping from height into (deep) water. Obviously the OP won't be holding their helmet onto their head, but in general, elbows tight to sides, feet first, cover mouth/nose. – bob1 Feb 18 at 9:20
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    Important things to keep in mind when jumping like this from heights, keep your arms crossed with elbows in tight to your body, legs crossed with toes pointed, and clench your butt – Malco Feb 18 at 14:54
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    @Malco ^ Hahahaha omg – Andrew Feb 18 at 21:01
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    From a physics perspective a larger person will have greater momentum (mass x velocity) - so yes. Basically from 30 m, you'll be going at 87 km/h/54 mph - that's very fast and water is very hard at these speeds, so the more stream-lined you can make yourself, the better - a fat person will have greater spread than a skinny one, so they'll most likely get hurt more is my guess. – bob1 Feb 18 at 21:32
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Well, first thing first, 100' (30 metre) is likely not to end well for you. So really the question stops being valid way before that.

Second, if you've ever spent anytime diving and had the pleasure of a bellyflop, you know you don't want to put yourself into any kind of uncontrolled tumble, and that means minimizing your rotation from your starting position. Feet first on land, feet first in the water, would be my thinking. Of course, if you know what you are doing diving then you can certainly aim for a cleaner jump and go in head first. That's what the Acapulco cliff divers do. But they wouldn't be asking this question.

Third, even if you know how to dive in cleanly, you don't necessarily know how deep the water is at the bottom of the cliff. That means that diving head first puts you at extra risk - better to hit the bottom with your feet than your head.

So, don't do this. Don't jump off cliffs without knowing exactly what's underneath. Ever.

I personally know one guy who is paralyzed for life because he forgot how much of a tidal difference there is where I live. And just saw a plaque commemorating someone who died for the same reason yesterday (there are 2 plaques there, Wiki's is about the legend).

If I had to jump, I know I would jump feet first however. I am not that comfortable doing head first, even though I have done it up to about 20-25' (6-8 metre) high. If you're a beginner at high jumps, head first is just that much trickier to get right and in any case it leaves you more at risk from hitting your head.

From wikipedia, High Diving:

Health implications Some research suggests that the impact associated with high diving could have negative effects on the joints and muscles of athletes. To avoid injury to their arms upon impact with the water, divers from significant heights may enter the water feet first.

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    I agree with your conclusion - head first carries the risk of undercommitting and hitting the water badly. But I'm not sure there's much more risk if well executed: if you hit the bottom feet first you can still break your back and then drown while conscious (worst case of course). – Chris H Feb 18 at 8:59
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    gotta disagree. first, you bleed speed way quicker landing on your feet in a sitting position than in a clean head first dive. you can probably dive from 10' feet and have minimal impact in 6-8' of water, esp if you put out your arms. second, any hit to your head/neck is dangerous, while our feet are made for landing on. I thought of the "clean dive" from heights pushing for head first from very high and with a trained athlete, but the wikipedia page isn't all that supportive of the concept either, see my quote. – Italian Philosophers 4 Monica Feb 18 at 15:17
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    If you land on your backside in a sitting position - a small error if you're aiming for feet first - you'll do yourself a lot of damage. Here's a paper on damage from landing on the feet (not specifically on water) – Chris H Feb 18 at 15:31
  • I don't want to be unpleasant here, but suggesting that head first is safer, or not more risky, than feet first, unless you absolutely know 200% what the depth is and that you can clear it, is just totally irresponsible, no matter how you present it. That's my opinion and you are welcome to yours, but I wanted to put that on the record because I consider it to be a core safety concern. Now, on extreme heights, with skilled divers other considerations may come into play, see Medievalist's answer. But not 99% of the rest of the time and certainly not for casual divers. – Italian Philosophers 4 Monica Feb 21 at 20:41
  • assuming you're replying to me, read what I wrote first. My words, added emphasis: "not sure there's much more risk" (to head first) . I was highlighting the very real risks of serious injury or death from landing feet first, that you at least initially brushed off, and not recommending a head first entry. I stand by that, and I'm out of here – Chris H Feb 22 at 13:46
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Feet first. This has been well covered in other answers.

Keep your body nice and straight, use your abs to support yourself, point your toes. All the things that competitive divers do to make less splash will also make your entry into the water easier. Take a deep breath, you will need it (about 2.5 seconds of fall time, plus however long it takes you to get back to the surface!).

However, once you enter the water you should do a modified "save". Basically the opposite of above, after you enter the water you make your surface area larger so that you stop going down as quickly as possible. There are complicated techniques for doing this in competitive diving to create the appearance of a perfectly straight dive, but you don't care about that so yours can be much simpler. 1) Wait until you are fully in the water. 2) Go limp. Let your legs bend up a little, almost like you're sitting in a chair. 3) When you feel comfortable with your speed relative to the strength of your arms, use your arms to do a flip under water.

Then kick kick kick back to the surface, you will be low on air.

(I used to do not-very-competitive diving, and the same dive with and without a save was the difference between landing hard enough to stub a toe on the bottom of 13 feet, vs barely going below the surface.)

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  • Is “wait until you are fully in the water” really how it works? It seems that this would go way too fast to actually react to the impact. – leftaroundabout Feb 19 at 7:41
  • @leftaroundabout In competitive diving, you save literally at the point where you're entering the water, to make your dive appear straighter (your legs would tip over from rotation, but instead you take the rotation into your upper body and leave your legs straight up). I don't think that's doable from this height, but I wanted to point out that you shouldn't even try it since if you go too early bad things happen. Likewise, a competitive save would swim with the arms right away, but not a good idea from that height--just wait until you've slowed down a bit. – user3067860 Feb 19 at 15:41
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The New Yorker has an interesting and sad article on people jumping off the Golden Gate Bridge. According to the article:

The rare survivors always hit feet first, and at a slight angle.

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1

XY-question frame challenge.

The only way to win the game is to not play.

If you were to be jumping in, then the other answers give insightful food for thought. But that's a huge, colossal if, especially given your use case. So here comes the party-pooper...

As long as you are even moderately well prepared I would be willing to bet a lot of money that the odds of "I'm in a The Great Outdoors survival situation where I need to jump 100 feet off a cliff into water" are very slim. I think you're more likely to get struck by lightning on a clear day where no signs of lightning were present (supposedly, that happens).

Originally I was much stronger in my wording. But thanks to @BlackThorn for pointing out there are use cases similar enough to what the question asks for that they should also be seriously considered. BlackThorn wrote:

Fire on a cruise ship, fire on an aircraft carrier, friend falls off of cliff and you want to rescue him before he drowns (and you jump because you are confident you can survive the fall to rescue him). The last example literally happened to a friend of mine with an 80 foot cliff and he saved his life, holding his friends face above the water until paramedics arrived.

Ship Fire

Even if there is a fire on a ship, that doesn't mean you're likely to be forced to jump from the top, but that could be a possibility. If you are on a tall ship and concerned about fire safety, a safer strategy would be to review the ship's fire evacuation routes and procedures. In case of fire, a smart evacuation is better than a frantic high jump.

Cliff Rescue

In the case of a friend falling from a cliff, again, that does not automatically mean someone should immediately jump in after them, especially if you don't know the safety situation at the bottom. In all emergency rescue situations, you need to ensure your own safety as well otherwise you endanger both yourself and the other person.

If a friend falls from a cliff, do not immediately jump over after them. As quickly as you can, scan the bottom for safety hazards. Wait a second to see what is happening to the person who fell as well.

I am happy for BlackThorn's friend that the outcome was favorable. However, this anecdotal evidence does not mean you should throw logic to the wind, and hopefully the heroic friend performed the rescue safely.

An 80 to 100 foot fall takes between 2-3 seconds according to a quick Google query. Human reaction time means that a rescuer is likely to be at least a second or two behind to begin with. At that point you might as well wait the 1 second to see how the victim lands since they might not even need rescuing. And if you are wearing any very cumbersome clothing you should remove it first: I know some of my boots would make it impossible to perform a water rescue in, so taking even 10 seconds to remove them would be better than jumping in with them on.

So work quickly to save the person, but don't rush to the point of making the situation worse. The old "hurry up and wait."

It has also happened that people jumping from heights into water have landed on a person at the bottom and killed them. It would be a tragic accident if a heroic effort to save someone who would not have died anyway led to both the victim and the hero dying together in vain.

If you are absolutely sure that this is actually necessary, then jump in like a rigid vertical pencil.

Realistic possibility of survival jump

The "jump off a cliff to survive" trope is exciting but not realistic.

Maybe this question was inspired by a scene I've heard about where Bear Grylls supposedly did something similar and made some people thing it was a reasonable survival tactic. I haven't seen the scene myself.

This use case is simply not realistic and is a dangerous view of wilderness survival. Even if you create a highly contrived scenario where you make it seem like this is the best option, I would still take my chances sitting tight and doing my best on the high ground. Your survival odds are likely higher.

Even if you are severely dehydrated and need the water at the bottom of the cliff, in that case I still might stay up top. To be so dehydrated that you would risk the jump means you're probably also so dehydrated that you 1) aren't thinking as clearly and are more likely to make bad choices, and 2) lack the coordination and strength to perform the jump technique well and will have even higher odds of severe injury or death.

"I still want to prepare for this rare situation anyway!"

Ok, then here's what you can do that will benefit you way more. An ounce of prevention is worth a pound of cure.

Predators: To deal with predators bring defenses and learn to use them. Bear spray, knowledge of local predators and how to remain safe around them, defensible positions (ie: don't put yourself between a cliff and predator to begin with).

Forest fire: You might still be at risk at the bottom of the cliff. You might also make it harder for rescuers to find or reach you by making such a change to your location.

Wilderness Survival: Everyone needs to get the idea out of their head that such risky actions are a part of real wilderness survival training. If you're in a wilderness survival situation, you need to avoid such risks at all costs.

Out of all the rare cases where you might otherwise be tempted to jump, in most of them you would probably be better served by bringing bear spray and bringing an emergency locator beacon to signal for help and let rescuers know your location.

Climbed up a rock face and dropped your gear? Activate your beacon. Realize a forest fire is nearby? Activate your beacon. Being hunted or attacked? Active your bear spray. Any other situation where you don't have to jump right this second? Active your beacon.

"But what if the beacon fails?" That's possible, sure, but what are the odds that will happen coinciding with an animal attack coinciding with a cliff-you-animal sandwich, coinciding with survivable water at the bottom of it? Not convinced? Get a second beacon as a back up.

Think ahead for situation-specific emergency backups, like an emergency waist pack with an extra rope and/or beacon. Similarly, if this is a concern plan for it before a trip where you're around cliffs: What could go wrong, and how could I mitigate that so I wouldn't have to jump?

Summary

Don't jump! Just bring defenses and a beacon and plan ahead, as mitigating the situation beforehand has much higher chance of success than dealing with it after.

If you do somehow manage to have no choice at all but to jump, and you decide to jump despite your terrible luck at this point, then look to the other answers and pencil drop in straight and rigid.

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    Fire on a cruise ship, fire on an aircraft carrier, friend falls off of cliff and you want to rescue him before he drowns (and you jump because you are confident you can survive the fall to rescue him). The last example literally happened to a friend of mine with an 80 foot cliff and he saved his life, holding his friends face above the water until paramedics arrived. – BlackThorn Feb 19 at 20:21
  • appreciate the response but however unlikely the situation may seem, im just curious to know what would be the best way to survive a fall like that – mph85 Feb 19 at 22:11
  • @mph85 Oh, I agree. And I'm actually glad you asked, as I think it's a great question. And I'm glad to have read the other answers that answered you more directly. I think it's good information, and you and I are better off for having read it. But because it's so unlikely, I think that reading those answers is all I need to do to prepare; it's a cost-benefit trade off thing. And I still recommend more time and effort spent on the other things I mentioned even to prepare for this situation. – Loduwijk Feb 20 at 17:33
  • Aircraft carriers and many cruise ships have decks that are actually quite a bit taller than 100 ft above the water, even over 200 ft. If I worked on either type of vessel, I would certainly want to prepare for the event that I would need to find quick egress overboard. You are right to suggest that you ought to avoid jumping if at all possible, but I think you significantly underestimate the situations that might require such action. – BlackThorn Feb 20 at 17:54
  • @BlackThorn As I said, I was answering the question very directly: jump from a cliff. Not jump from a ship. I think that my original answer was right on if you take a very narrow look at OP's specific use case and put blinders on to all similar situations, but taking a wider view now (thanks to you) I realize the jump information is even more useful. Check out the edit I just finished. It removes the extremely strong "1-in-10B" type phrasing, includes the wider point of view, and I think is a better answer now. – Loduwijk Feb 20 at 19:07
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I just want to add one thing the other answers didn't emphasize enough : keep your arms along your body !

Don't put them above your head, don't spread them like if you were a bird ; keep them close !

If you don't... well, you're just Strappado'ing yourself.

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Jump feet first and rotate like a drill. This will slow you down upon entering the water so you dont hit bottom.

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  • Interesting. Can you actually have this level of control? Would your rotation slow down significantly as you fall? Also, wouldn't the drilling make you go faster? I would think that might provide a mechanism for the water to be displaced more easily or something. – Andrew Feb 18 at 21:06
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    @Andrew: If you were a trained olympic style diver, you might have this sort of control from a stationary jump, normal people not so much. The real risk here is imparting a tumble and ending up in a posture that is not optimal for entering the water and doing yourself serious injury. I doubt that the rotational speed that anyone could impart would be enough to have anything other than a minor effect. – bob1 Feb 18 at 21:41
  • Every time I see this answer I picture in my head an anime character taking a running leap off the cliff, momentarily stopping in the air as they begin to spin, then shooting down like a drill. As if it's some kind of fighter-game move or anime DBZ'ish move. – Loduwijk Feb 21 at 16:18

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