Can lightning hurt a person in freefall?
May 21, 2010 3:57 PM   Subscribe

I'm an amateur skydiver, on my last jump at around 9000 feet I saw a lightning bolt in a cloud a mile or two away. In 170 jumps I've blown through plenty of clouds, sometimes with rain, without ever giving lightning a thought. Although ungrounded, am I likely to be struck in freefall? Would being struck in freefall damage or melt tightly packed nylon?
posted by mewmewmew to Science & Nature (10 answers total) 12 users marked this as a favorite
 
Since commercial planes get hit by lightning during flight, I assume a human could be as well, however if the plane you're hitching a ride from has a somewhat competent pilot, he/she should be steering clear from weather systems or aborting the jump.
posted by hungrysquirrels at 4:26 PM on May 21, 2010


Planes get hit by lightning apparently once a year on average. So I guess it's possible. They're made of metal though and present a better path for current to flow versus air. The human body also has lower resistance than air, but a lot more than an airplane so I'm not sure whether it's low enough to "attract" lightning. Certainly it's theoretically possible to simply be in the wrong place at the wrong time and be right where the lightning both would have gone anyway but the odds are pretty low.
posted by GuyZero at 4:27 PM on May 21, 2010


I know you're asking specifically about mid-air lightning strikes, but it seems your most critical concern would be updrafts and downdrafts. Parachutists have free-fallen near storm clouds only to be sucked in and lifted skywards more than 3000 ft, held aloft for 30 minutes, and carried 16 miles away from the dropzone Yikes.

That may seem scary, but it's just a mere inconvenience when compared with William Rankin's first and only surviving fall through a top of a cumulonimbus thunderstorm cloud. In 1959, Rankin was forced to eject from his F8U fighter jet at 48000 feet, a harrowing 40-minute journey fraught with decompression that caused bleeding from his eyes, ears, nose and mouth, frostbite, pounding hail that induced welts and bruses, lightning described as "blue blades several feet thick" that gave him "the distinct feeling of being sliced in two," thunder described as "unbearable physical experiences," and sheets of rain that forced him to hold his breath to keep from drowning. Miraculously, he landed safely near a housing development and caught a ride back to the drop zone nine miles away. Bad. Ass.

I'm just curious what skydiving outfit would possibly have the audacity/liability to take clients up in storm conditions. Seems insanely risky, albeit terribly exciting.
posted by prinado at 5:59 PM on May 21, 2010 [22 favorites]


In 170 jumps I've blown through plenty of clouds, sometimes with rain, without ever giving lightning a thought.

Presumably you are aware that it is illegal to jump through clouds, at least in the U.S. and Canada. You must be at least 2000 feet horizontally away from any clouds.
posted by JackFlash at 6:03 PM on May 21, 2010


you should change dropzones.
posted by spacefire at 8:18 PM on May 21, 2010


FWIW this was in Europe, and I am aware of US cloud regulations. This particular jump would definitely fall within regulations. The lightning was at least a mile away, my line of flight was clear.

What I'm really just curious about, is if I happened to be in the absolute worst place at the absolute worst time, would I be affected at all? Dead? Would I even know I was in the path of lightning?
posted by mewmewmew at 9:02 PM on May 21, 2010


Just so you know you can be struck by lighting even if there are no clouds around\above you. You being a mile away and thinking you are safe is off base.

When I lived in Florida this "bolt from the blue" senario would happen to people about every summer.
The sky would be completely clear, their would be a storm brewing miles away, and then the next bolt would hit some guy golfing.

Scientists have documented lighting bolts traveling as far as 25miles away.


Basically, if you can hear thunder the next strike COULD hit around where you are even if you don't see clouds.

As far as your question, it really depends on the strength of the bolt and what it ends up doing.
I think the theoretical skydiver could easily suffer some pretty bad burns. The bolts themselves can be 54,000 degrees Fahrenheit. The air is superheated around the bolt because of the extreme temperature. The shock wave that happens because of the superheating (thunder), will be traveling faster than the speed of sound and could easily knock the sky diver around.

I'd love to see an experiment of throwing a dummy with a bunch of sensors out of a plane in t-storms waiting for it to get hit.

So: You would be affected in someway, no idea if you would die, and yes you would most definitely know you were in the path of lightning.

I'd suggest just reading about lightning hitting grounded and ungrounded objects it's pretty fascinating and unpredictable.
posted by zephyr_words at 10:27 PM on May 21, 2010 [1 favorite]


The lightning was at least a mile away, my line of flight was clear

Well its pretty dangerous to fly close to thunderstorms in a light airplane. The Aeronautical Information Manual (sec 7.1.29) says

"Do avoid by at least 20 miles any thunderstorm identified as severe or giving an intense radar echo. This is especially true under the anvil of a large cumulonimbus." I'm sure you could get closer to smaller storms, but 1 mile is pretty close (for the plane making the drop).

I would think that a lighting strike on a jumper would have similar effects to getting struck when you're on the ground, that is to say not good. But I can't see that it would be any more dangerous then being out in the open on the ground under a TS. I would be more worried about updrafts once your chute is deployed. I don't sky dive, but hang gliders and paragliders treat TS will a lot of respect because of the danger if getting sucked into one. It's called cloud suck, and the story of Ewa Wisnierska is worth a read.

Are the VFR cloud clearance rules significantly different in Europe? In the US it makes perfect sense for sky divers to follow the same visual flight rules as aircraft. Don't go in the clouds because you might hit an instrument rules aircraft you don't know about and can't see. Why would that be different across the pond?
posted by Long Way To Go at 10:39 PM on May 21, 2010


Just had another thought. If not fried, it could simply knock you unconscious (think tasering), so, unable to pull the chute, even if it was still ok. Even being disorientated by it could be disastrous. Assuming jumping with others though, I believe there's also a chance of rescue if someone nearby notices you're in trouble, on the other hand, if they were nearby, there's a chance of them being struck at the same time. Anyway, I'm just musing.
posted by hungrysquirrels at 11:16 PM on May 21, 2010


it could simply knock you unconscious (think tasering), so, unable to pull the chute, even if it was still ok.

All of the rigs I have seen have an automatic deployment system for this sort of situation.
posted by C17H19NO3 at 8:38 AM on May 22, 2010


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