PDA

View Full Version : Lightning Safety Guidelines



veteran
12-03-2009, 11:00
LIGHTNING SAFETY GUIDELINES

http://facultyfiles.deanza.edu/images/donahuemary/lightningstorm.gif


This information from www.explore-rocky.com/hiking/lightning.html has been compiled from resources from the National Lightning Safety Institute and the National Outdoor Leadership School's "Lightning Safety" publication.

How Does Lightning Strike?
Lightning strikes fast. The whole process usually takes a few milliseconds. Stepped leaders of electric current leave a cumulonimbus cloud and some leaders move toward the ground. They appear as many branches, but only 1-2 branches will reach the ground. Approximately every 50 meters a new step leaves each leader and heads in a fairly random direction.
If a leader gets 100m from the ground, positively charged streamers start rising from the closest grounded objects towards the negatively charged leader. As soon as the leader is close enough to a streamer, it shoots directly to that streamer and “blazes a trail” for a significant charge (a return stroke) to shoot from the ground to the cloud.

Most ground strikes occur immediately below a cumulonimbus cloud. Rarely, a bolt of lightning can move horizontally and strike somewhere “out of the blue” (out of the blue sky) as far as 10 miles (16km) away. These horizontal strikes are rare and unpredictable, so they shouldn’t affect our decisions. Lightning tends to hit elevated sharp terrain features like mountain tops. Lightning tends to hit tall trees in open areas, with objects twice as high receiving roughly 4X the strikes. Lightning tends to hit bushes in the desert if the bush is sticking up higher than the flat ground around it. Lightning can still hit flat ground or water, but more randomly than it hits elevated objects. Even a few less feet of height can make a difference in improving your odds of NOT being the struck object. This is why the first part of getting into the lightning position is lowering yourself down.

How Can Lightning Hurt Us?
Direct strike - A stepped leader of current connects with a streamer coming out of your body, then the return stroke passed through you or over your body's surface. The return stroke is the most significant electrical event of a lightning strike and has a typical current of 30,000 amps. (Household current is 15 amps.)

Streamer Currents - Fast, high-current pulses are launched from the tops of many elevated objects near each leader as it approaches the ground. Streamer currents, while much smaller than the return stroke current, are still large enough to cause injury or death to humans.

Ground Currents - Ground currents occur with each strike and cause roughly half of all lightning injuries. Typical lightning-to-ground strikes inject roughly 30,000 amps into the Earth. How far the current flows varies wildly since the magnitude of strike current and ground conductance varies. But the closer you are to the direct strike, the stronger the ground current.
You can MINIMIZE exposure to ground potential differences and ground currents by: keeping your feet close together, by NOT assuming a prone position, and by assuming the lightning position. These actions can help MINIMIZE the amount of ground current going through your body. We’ve always been told to sit on a insulating item such as a pack, but this action is dismissed by many experts.

"There is a great deal of wishful thinking in the outdoors community that sitting on a pack or putting down metal can reduce or eliminate lightning danger," warns Ron Holle, of the National Severe Storms Laboratory. "Unfortunately, it doesn't matter what you're sitting or lying on. The flash came from 5 to 8 miles up in the cloud and has 30,000 amps, so it will penetrate absolutely anything."

Surface Arcs - High current surface arcs appear to be associated with some fraction of all cloud-to-ground discharges, during the return stroke. They appear in photographs as bright arcs of light radiating from a strike point like spokes of a wheel, in the air just above the ground’s surface. These long, hot horizontal currents have been measured up to 20 meters in length and may get longer. If you are in the path of a surface arc you are likely to conduct some of the surface arc current through or over your body. Since surface arcs emanate from the base of trees struck by lightning, never seek shelter near a tree.

Other forms of lightning damage can include: Radiation – the visible, infrared and ultra–violet radiation near the strike point, which can damage your vision. A thunder pulse can damage hearing temporarily or even permanently. During any stage of a thunderstorm, the electrostatic field can be enhanced enough around grounded objects to cause brush or point discharge (a corona). At night, you may be able to see corona as a faint glow from sharp rock outcrops or the tops of bushes or trees. You may hear corona as a sizzling or buzzing sound. Even if you can't see or hear corona, you might smell ozone, one of the chemical products of point discharge in air. If you feel hairs on your head, legs or arms tingling and standing on end, you are in an extremely high electric field.

The response to any of these signs should be to instantly (seconds matter) drop and move away from all packs, remove metal shoe fittings, spread out, and adopt the lightning position. Do not ignore these signs and do not try to run to safety, unless safety is literally seconds away. If any of these signs are detected, the probability of a close discharge is high and every effort should be made to minimize injuries and the number of injured.

How Can We Reduce Lightning Risk In The Backcountry?
There are things you can do to reduce risk during a thunderstorm, but you can never get as safe as you could be in town. Some risk reduction factors, like taking off a metallic belt buckle, might reduce burns but have little to do with avoiding becoming a fatality. But there are five actions that can reduce your risk:

1. Time visits to high-risk areas with weather patterns
2. Find safer terrain if you hear thunder
3. Avoid trees
4. Avoid long conductors
5. Get in the lightning position

Timing activities with safe weather requires knowledge of local weather patterns. You need to set turnaround times that will get you off of exposed terrain before storms hit. Begin your turnaround if you hear thunder (which means lightning is one to ten miles away.) In calm air, you can hear thunder for about ten miles. In turbulent air, you can hear the thunder for about five miles. In a driving storm, you may only hear it out to one mile. Some parties in rain storms have been struck before they heard any thunder at all.

Safer terrain in the backcountry can decrease your chances of being struck. High pointed terrain attracts lightning to the high points, and even to the terrain around it. Avoid peaks, ridges, and significantly higher ground during an electrical storm. If you have a choice, descend a mountain on the side that has no clouds over it, since strikes will be rare on that side until the clouds move over it. Once you get down to low rolling terrain, strikes are so random you shouldn’t worry about terrain as much. If you are exposed to lightning, you need to get in the lightning position as soon as possible, which obviously means you stop moving to safer terrain at that point. Many people have died while upright and walking to safer terrain, but no one has died while stopped in the lightning position. Move to safer terrain as soon as you hear thunder, not when the storm is upon you.

In gently rolling hills, the lower flat areas are probably not safer than the higher flat areas because none of the gentle terrain attracts leaders. Strikes are random in this terrain. Look for a dry ravine or other significant depression to reduce risk. Wide open ground offers high exposure during an electrical storm. Avoid trees and bushes that raise above the others, since the highest objects around tend to generate streamers. Your best bet is to look for an obvious ravine or depression before the storm hits, but when the cloud is over you, spread out your group at 50’ intervals to reduce multiple injuries and assume the lightning position.

Naturally wet ground, like damp ground next to a stream, isn’t any more dangerous than dry ground, so don’t worry about this. It used to be said that wet ground was more dangerous, because it conducted more ground current, but wet ground actually dissipates ground current faster. Neither wet nor dry is considered more dangerous than the other. Standing in water should be avoided. Dry snow is an insulator, but wet snow is a conductor. This should make travel on dry snow safer than on bare ground, because it will be harder for a person to generate streamers or conduct ground current. Avoid cave entrances. Small overhangs can allow arcs to cross the gap. Natural caves that go well into the ground can be struck, either via the entrance or through the ground. You should never be anywhere near any metal handrail, wire or cable during a storm. Avoid trees because they are taller than their surroundings. Tall trees are especially adept at generating streamers that attract strikes. If you need to move through a forest while seeking safer terrain, stay away from the tree trunks as you move. You should also avoid open areas that are 100m wide or wider. Lone trees are especially dangerous: the laws of probability say you are hundreds of times safer in a forest with hundreds of trees than you are near a lone tree in an open space.

“Cone of protection” from trees and cliffs is an arguable concept and has no place in lightning safety education anymore.
Lightning has been photographed striking 100 meters from 200 meter towers, and surface arcs have been photographed exactly where “cones of protection” inferred we were all safe.

Assume the Lightning Position when at risk. This will reduce the chances of getting a direct strike and it may reduce the other effects of lightning, but it offers no guarantees. The data says that no one in this position has ever been hurt. This position includes squatting (or sitting) and balling up so you are as low as possible without getting prone. Wrap your arms around your legs, both to offer a safer path than your torso for electrons to flow from the ground, and to add enough comfort that you will choose to hold the position longer. Close your eyes. While the prone position is lower, being spread out increases potential for ground current to flow through or across you. Keep your feet together so you don’t create potential for current to flow in one foot and out the other. Don’t touch metallic objects like ice axes, crampons, tent poles or even jewelry. You won’t get a warning that a strike is imminent because the lightning event from cloud to ground and back occurs faster than you can blink an eye, so stay in the lightning position until the storm passes. This position reduces the chances of lightning injuring you as badly as if you were standing, but is no substitute for getting to safer terrain if it is immediately available. A dangerously close strike actually offers a moment of opportunity to move, while the electrical field rebuilds itself. But in wide open country or gentle rolling terrain there are no simple terrain advantages, so use this position to reduce exposure. If you are concerned enough to use the lightning position, have your group dispersed at least 50’ apart to reduce the chances of multiple injuries.

Don’t rely completely on nifty sayings like “Up high by noon, down low by two.” Use such suggestions in planning your hikes. Lightning can strike at any time of the day. The National Lightning Safety Institute reports that most injuries occur in the summer months between 11:00 am and 9:00 pm. Plan on hiking back down the trail before the afternoon rolls around, and even earlier when hiking in the tundra. As you’re hiking, look up at the skies every 15 minutes and know how to read the ever-changing weather conditions. Again, if you hear thunder and are above treeline, turn back immediately. If you see dark clouds with flat bottoms developing, it’s a good sign that thunderstorms will develop and it’s time to head home. Stay alive and come back to hike the trail another day.

If someone in your hiking party is struck by lightning and is not breathing, you should immediately attempt to restore life by giving CPR. Their bodies do not retain the electrical charge and are safe to handle, and most people can survive a strike if given proper treatment right away. Send someone in your party to get help right away. Have one person stay with the victim until help arrives. Keep victims awake and hydrated, and make sure he/she urinates frequently. Conscious victims with injuries will probably survive, but all should have a thorough medical examination.

Some Web Sources for Lightning information:
http://rendezvous.nols.edu/files/Cur...Guidelines.pdf

http://www.lightningsafety.com/nlsi_pls/ploutdoor.htm

http://faculty.deanza.edu/donahuemar...toryReader$583

Spokes
12-03-2009, 12:57
Nikola Tesla would be proud. Thanks!

emerald
12-03-2009, 13:52
It might be a good idea to add the most exposed areas on the A.T. for those who do not know.

johnnybgood
12-03-2009, 17:47
Good idea emerald. Maybe a quick reminder to those starting their thru hikes in early spring. I guessing that there are statistics on reported lighting strikes in the vicinity of the AT by NOAA .

Avalanche1
11-28-2011, 12:29
Thanks for the info.

Rain Man
11-28-2011, 12:38
Does this translate from the Rockies to the Appalachians?

Rain Man

.

SawnieRobertson
11-29-2011, 10:45
The only info that this research group has previously published that is not in this article (that I recall from living on the Front Range) is that three-sided buildings offer no protection from lightning. I just hated to know that since they certainly give us a feeling of comfort as the downpour pours. In their list of what to get away from, they did not mention our hiking poles or our tents with metal poles. That has always given me pause. The other question that
lurks in my mind is the safety of hammocks, hanging from two tall-enough-to-be-stout trees. But mostly I want to thank you for passing on this article, Veteran.--Sawnie

Theosus
11-29-2011, 21:09
I guess I should pay attention to this one. I love photographing lightning, and many times as I've been out in an open field next to my metal tripod as a storm approaches, I've had that "What the Hell am I doing?" feeling.

Mike2012
11-29-2011, 21:14
I am packing a smart phone so I can check the radar and plan my hiking for lightning safety. I reckon I'll hike extra miles to avoid being exposed on high ground at the wrong time. Strong storms will provide me with an excuse for an in town zero as well. I know reception is spotty so I'll keep my common sense turned on as well.

RWheeler
02-17-2012, 10:52
Hi friend, I just hated to know that since they certainly give us a feeling of comfort as the downpour pours. In their list of what to get away from, they did not mention our hiking poles or our tents with metal poles.

The article does specifically state that you don't want to be near tent poles, and it generalizes to items as metallic anyway - if you can't figure out that you shouldn't be holding on to the giant lightning rods, well... you forgot to pack your common sense on this trip. Although the poles would serve more as a safety lightning rod, providing an easier route for the lightning to get directly to the ground. As long as you aren't laying in a puddle of water inside of it, the path really should be just through the pole. But you definitely don't want to be inside a tent if there are trees around you, in the event that one is struck and will drop limbs or something on you.

ekeverette
02-17-2012, 11:24
i suppose if i'm in my tent at night... i just stay put and pray..... if out on the trail and a bad storm comes up, i understand the prone position... but do you take your backpack off, since it has metal in it... walk several yards from it and get into the prone position?... lighting scares me worst than anything... i've been zapped by it, and will not ever forget that surge of electricity!... i was struck indirectly, but i still hurt.

RWheeler
02-17-2012, 11:56
i suppose if i'm in my tent at night... i just stay put and pray..... if out on the trail and a bad storm comes up, i understand the prone position... but do you take your backpack off, since it has metal in it... walk several yards from it and get into the prone position?... lighting scares me worst than anything... i've been zapped by it, and will not ever forget that surge of electricity!... i was struck indirectly, but i still hurt.

You don't want to go prone, sure you're closer to the ground, but then your surface area with the ground makes you way more susceptible to ground currents, and you also give anything an easy path that includes your chest. Not ideal. Squat kinda like you're over a cat hole, but get your knees close to your chest and wrap your arms around them. Keep your butt hovering. That way if you do get hit, the lightning will most likely travel across your skull, down an arm, into a leg, and down into the ground.

But yeah, I'd throw my backpack off and probably be about 20' from it if possible. Even if you don't have a frame in the pack, the zippers might greatly throw off the path of a strike. Worst case scenario for ditching your pack is that it gets hit and bursts into flames or something. But then at least you aren't attached to it. Or someone steals it. And honestly, if someone is going to run around and steal stuff during a thunderstorm, then they can have it. That'd be a fun story to tell. "Yeah, so I was just squatting on the trail trying to avoid getting hit by lightning and this dude came by screaming, snatched up my pack and continued to run. Joke's on him, though. I just resupplied so he has to carry that extra 12lbs."

JustADude
02-17-2012, 12:00
So, is it better/safer (if the thunderstorm can't be avoided) to stay in a shelter or in a tent? (from a lightning prospective)

ekeverette
02-17-2012, 14:09
that's what i want to know. if i'm in my tent, shelter close by in the middle of the night, and one of those horrific lightning storms comes up... do i haul ass to the shelter, which will be slam full..... i think yes, cause i really don't like lightning! as far as getting caught on the trail, i'll shed the pack and get in the squatting position.... these storms scare me way more than any bears, or snakes.... i'll find out.

Tinker
02-17-2012, 23:42
The article does specifically state that you don't want to be near tent poles, and it generalizes to items as metallic anyway - if you can't figure out that you shouldn't be holding on to the giant lightning rods, well... you forgot to pack your common sense on this trip. Although the poles would serve more as a safety lightning rod, providing an easier route for the lightning to get directly to the ground. As long as you aren't laying in a puddle of water inside of it, the path really should be just through the pole. But you definitely don't want to be inside a tent if there are trees around you, in the event that one is struck and will drop limbs or something on you.

I remember running through a lightning storm dragging my poles on the ground hoping that if I got hit it would travel down the poles to the ground without going through my body. I laugh about it now, but it was pretty serious then.
Tenting or hammocking in serious weather is probably best done in a grove of the smallest trees you can find (that will hold your hammock securely). Less likelihood of a lightning strike or heavy branches falling.
I have never been fond of tin roofed shelters in electrical storms. Many years back all the members (with one exception) of a boy scout troop were killed in a shelter while laying on metal frame bunk beds with wire mattress supports. I think I remember this being on the AT. I think the survivor was the only one not in a bunk.
Fwiw, I believe that all metal and wire bunks have been replaced since this long ago incident.

FredSwartz57
08-26-2017, 10:18
I have learned to read the Clouds and watch them during the day, they seem to be a good indicator as to what the days weather will bring. This way I know if I have to pick up my pace hiking or spend a little more time in the woods.

gpburdelljr
08-26-2017, 12:35
It might be a good idea to add the most exposed areas on the A.T. for those who do not know.
Good idea, why don't you do that.

Tipi Walter
08-26-2017, 12:46
i suppose if i'm in my tent at night... i just stay put and pray..... if out on the trail and a bad storm comes up, i understand the prone position... but do you take your backpack off, since it has metal in it... walk several yards from it and get into the prone position?... lighting scares me worst than anything... i've been zapped by it, and will not ever forget that surge of electricity!... i was struck indirectly, but i still hurt.

Comprehensive article! What about prone on a ridgerest or thermarest? Who wants to test this theory? I'm usually supine on my pad during the worst events.

The article left out my main lightning technique---Sit in tent and wait to die, otherwise pray to the most significant God of your choice. Ekeverette has it right---Just stay put and pray.

Site selection is usually not pertinent when these storms hit in the middle of the night and you're already perched atop some mountaintop. And grabbing your rain gear at 3am to run off the mountain and leave your tent in a panic is no guarantee as a bolt could just as easily blast your fleeing form halfway down the hillside.

TTT
08-26-2017, 13:04
Thanks for the article - appreciated.
Have any of the old abandoned houses on the trail been hit by lightening? (The ones that can be identified by chimneys) Apparently building a fire and having a plume of warm smoke that rises above surrounding trees is a good conductor and path for lightning to follow.

Malto
08-26-2017, 17:17
I was just in a fairly hairy position while on a mesa at 11k in Colorado. I pretty much followed the advise given here but I would rather not repeat this event. I was squatting in a small depression huddled under my non-metallic umbrella. The white in the picture is hail accumulation. One last thought, about the only metal in my gear is my tent stakes. Never really thought about the lightning advantages of UL.
40144

JPritch
08-28-2017, 13:25
Decent read. Hitting the JMT in a few days and understand I'll be pretty exposed in some parts. I do alot of fishing and had some very close calls. Seen lightning touch down on the water around me while I'm gunning back to the dock. One of my graphite fishing poles began buzzing one night. I knew I had to get out of there quick! Man do I hate lightning. Definitely puts you in your place so to speak and shows you how powerless you really are.

JeffreyH
09-08-2017, 10:50
Decent read. Hitting the JMT in a few days and understand I'll be pretty exposed in some parts. I do alot of fishing and had some very close calls. Seen lightning touch down on the water around me while I'm gunning back to the dock. One of my graphite fishing poles began buzzing one night. I knew I had to get out of there quick! Man do I hate lightning. Definitely puts you in your place so to speak and shows you how powerless you really are.

I'm happy one of those close calls you had didn't become fatal.
Everyone must be careful while hiking, especially while hiking alone.

spfleisig
09-08-2017, 11:49
Well this seems to rain on the "lightening position" parade. This seems like many things, ask 3 experts, get 3 opinions.

The National Weather Service (NWS) stopped recommending the crouch in 2008. Why? The crouch simply doesn't provide a significant level of protection. Whether you're standing or in the crouch position, if a lightning channel approaches from directly overhead (or very nearly so), you're very likely to be struck and either killed or injured by the lightning strike. Rather than "what to do in a dangerous situation" NWS focuses on "what to do so you don't get into a dangerous situation," and, "if you do find yourself in a dangerous situation, how to get out of the dangerous situation."
◾Plan ahead, that includes knowing where you'll go for safety.
◾Listen to the forecast.
◾Cancel or postpone activities if thunderstorms are in the forecast.
◾Monitor weather conditions.
◾Take action early so you have time to get to a safe place.
◾Get inside a substantial building or hard-topped metal vehicle before threatening weather arrives.
◾If you hear thunder, get to the safe place immediately.

Promoting the crouch gives people the false impression that crouching will provide safety. Even to promote the crouch as a last resort when a person's hair stands on end gives people the impression that they will get a warning sign or that there is something that they can do in that situation which would prevent them from being struck.These beliefs could cause people to become apathetic and not seek a safe shelter before the lightning threat becomes significant.

So...what do you do when _____(fill in the blank)_____ and you can't get to a safe place? There is no safe place outside in a thunderstorm. NOAA's recommendations are based on safety. If you can't get inside a substantial building or hard-topped metal vehicle, you can't be safe. While there may be nothing you can do to lower your risk significantly, there are things you should avoid which would actually increase the risk of being struck. Those include:
◾ Avoid open areas.
◾Don't be or be near the tallest objects in the area.
◾Don't shelter under tall or isolated trees.
◾In the woods, put as much distance between you and any tree.
◾If in a group, spread out so that you increase the chances for survivors who could
come to the aid of any victims from a lightning strike.

Redbird2
12-03-2017, 10:38
Lightning is nothing to fool around with. It can be deadly. Check out this video of a lightning strike: https://youtu.be/Uunp45iO1RY

emmybecca
03-03-2018, 01:21
thanks for sharing the information

MuddyWaters
03-03-2018, 07:36
If you hike, you are going to have to engage in risky behavior occassionally.
Your chances of being struck are not very high. It goes with the activity.

One rule still applies.....dont be the tallest thing around.

Most of us have crossed high places in thunder storms because we were in wrong place at wrong time. Dont be foolish, but sometimes your choices are limited and you take risks.

Lightning can strike miles away from the actual thunderstorm , under clear sky. You cant go running off mountain every time you see a storm in distance. Well, maybe you can,but no one does.

Actually, contrary to above, the crouch does provide protection. Having feet touch ground close together minimizes potential for ground current to flow thru your body in a strike nearby. You dont have to be struck directly , to be killed. Many victims are not struck directly.

blw2
03-03-2018, 09:19
interesting old thread....
about "metal in your pack"
I seriously doubt if a pot or tent stakes in your pack are going to make a hill of beans worth of a difference. I don't think the metal in and of itself is an attractant or magnet to draw in the lightning. In my estimation, the metal thing is all about the conduction path to ground....the conductive umbrella shaft that increases your height &/or improves the path to ground.
This points to something I was considering when I bought trekking poles, knowing that I would likely end up with a trekking pole supported tent. I was reluctant to buy metal thinking they would be two lightning rods right next to me while I sleep. I did end up going aluminum and did end up with a zpacks duplex and I often second guess that decision.

3 sided shelters - maybe 35 years ago I was in a boat with my dad, a 23 ft Penn Yann with a flying bridge.....so we were in the cabin, motoring off shore in a thunderstorm. Lightning hit the top of the radio antenna and traveled through all the electrical system....everything that was turned on was literally melted into goo.... ever light bulb, the windshield wiper motor (the one that was off was fine), the engine's electronic ignition module.... everything. Everything was off was fine.
I was standing at the opened doorway looking out when it struck. The rain was splashing on the deck just outside was hitting my shins. Flash/Bang and I felt a zing. Much like touching a fully charged 9volt to your tongue.
Since that time I've learned a little more about lightning related to it striking aircraft. If it can pass through the structure or wiring, that acts like a faraday shield and never theoretically touches anything inside. The current is just trying to pass through to ground.
I'd recon that a metal roof shelter isn't such a bad place to be. It's really just the stray currents that might arc off the structure that might jump out to get you..... like the guy I knew once that told a story about lightning hitting a pole outside his house that got into the phone wire and jumped 10 feet or something from the phone on the wall in his kitchen to zap him..... so I wouldn't be touching anything on the walls that could be the path from that roof to ground and I'd be trying to stay away from the rain spray at the door, and I'd stay off the old wired phone on the wall.... but otherwise I'd rather be in a shelter than in my tent on a bald. I'd guess teh main bolt is much more likely to hit the taller trees around that shelter anyway.

Traveler
04-12-2018, 07:58
Gabby Johnson lives.

illabelle
04-12-2018, 09:05
Gabby Johnson lives.

Learned something new googling "who is gabby johnson"

NSHSDad
04-14-2018, 08:40
I've only had two scary experiences. Once I was above the tree line in the Pecos Wilderness area - I could see thunderstorms brewing and started to run to get off the exposed portion of the ridgeline and into the woods. The other was kayaking on a three mile crossing in coastal Maine, and a thunderstorm appeared that came off land bearing down. Both times, there wasn't much warning as the storms were partly hidden by land and other ridges.

walkinmyshoes
07-21-2018, 17:14
Interesting article, thank you, but... As you may know, according to the NOAA, over the last 20 years, the US averaged 51 annual lightning strike fatalities. And each year in the US, approximately 400 deaths are attributed to excessive natural heat. So you have 10x chances to be hit by heat, you know:)