...when the lighting strikes...

[NH_Mtn_Hiker]

The best way to avoid lightning is to stay home......

Ok, so that didn't mean to sound sarcastic, but its very true, and I mean every word of it. If there is a chance of thunderstorms, I almost always stay home, or I give myself at least 2 hours to get off the mountains. This Saturday I was supposed to hike Monroe but decided against it after reading the forecast. We did Monadnock instead and were treated to beautiful skies and got off the mountain hours before and thunder rolled through. Best way to avoid lightning....don't put yourself in its way...use common sense and don't hike when there is a chance.

On a personal side note....there is nothing else I am more scared of than lightning so I don't mess around. Just thinking about it and the experiences I've had in the past makes me nervous.

grouseking

I was struck by lightning inside my parents house. I happened to touch a metal cabinet the monent the bolt hit next to the house, it traveled in on an abandoned underground power line. I saw a brief flash of light in the window, then I was lauched into the air. I didn't feel anything until I was picking myself up off the floor... wondering why my feet hurt so bad, I sat back down and looked at the bottoms of my feet and they looked like burnt toast. It was a little sore to walk for a few days after that.

I no longer worry about lightning when I'm hiking.

 

[paul ron]

Ummmm.... that's lightening never strikes in the same place twice, not the same person.

OUCH!

 

[NH_Mtn_Hiker]

Ummmm.... that's lightening never strikes in the same place twice, not the same person.

OUCH!

I was referring to the fact that it can hit you inside as well as outside, so why worry about it? It's like worrying about being attacked by a bear while hiking, when more people are killed by dogs in and near towns.

 

[DougPaul]

I was referring to the fact that it can hit you inside as well as outside, so why worry about it? It's like worrying about being attacked by a bear while hiking, when more people are killed by dogs in and near towns.

Its about controlling one's probablity of being hit.

Getting zapped inside a house during a thunderstorm isn't that hard--talk on the (copper landline) phone, take a shower, hold on to an electrical appliance with one hand, a water pipe with the other, etc. (Ground currents or induced currents.)

According to Wilkerson, between 150 and 300 people are killed by lightning every year. If you decide to maximize your probability of being hit (eg stand on top of Lafayette waving your poles every time a thunderstorm comes by), you stand a pretty good chance of adding yourself to the list. If you are a bit more careful, you are rather less likely to end up on the list.

Doug

 

[sleeping bear]

The storm was pretty rough and violent, but I never thought it was too close....maybe 3 seconds at the worst between lighting and thunderclaps...

Previously I thought I had been taught to count the seconds between thunder and the lightning, as you mention here. I recently read in a couple of reputable sources, that you actually take the number of seconds and divide by five to get the distance. Puts a new perspective on things.... SCARY!

 

[DougPaul]

Previously I thought I had been taught to count the seconds between thunder and the lightning, as you mention here. I recently read in a couple of reputable sources, that you actually take the number of seconds and divide by five to get the distance. Puts a new perspective on things.... SCARY!

Sound travels at about 1000 ft/sec or 5 sec/mile. The flash, 186000 mi/sec.

So, the lightning is about a mile away for each 5 seconds between the flash and the thunder.

Doug

edit: corrected units: mph -> mi/sec

 

[SAR-EMT40]

Sound travels at about 1000 ft/sec or 5 sec/mile. The flash, 186000 mph.

So, the lightning is about a mile away for each 5 seconds between the flash and the thunder.

Doug

Correcting a typo (brain burp) on Dougs part. I know he knows the correct number, and units.

186000 Miles per second

Everything else in his post, as usual, is correct.

Keith

 

[Kevin Rooney]

Keith -

And while we're on the topic of correcting Doug (which is damn rare) - the speed of sound at 1000/sec is usually qualified by saying that measurement is at sea level, where air is the most dense, and therefore sound travels slightly faster there (if I remember my physics correctly).

Doug - am I right? How does the speed of sound compare at, say 5K? or 10K?

Kevin

 

[SAR-EMT40]

If you decide to maximize your probability of being hit (eg stand on top of Lafayette waving your poles every time a thunderstorm comes by), you stand a pretty good chance of adding yourself to the list. If you are a bit more careful, you are rather less likely to end up on the list.

Doug

For sure. The lightning can travel miles through free air. Your goal, as Doug's description so graphically shows is you just want to be the second best path of least resistance in the area. Not the best.

Anything you do to get yourself away from being part of the path of least resistance may save your life.

Keith

 

[grouseking]

I was struck by lightning inside my parents house. I happened to touch a metal cabinet the monent the bolt hit next to the house, it traveled in on an abandoned underground power line. I saw a brief flash of light in the window, then I was lauched into the air. I didn't feel anything until I was picking myself up off the floor... wondering why my feet hurt so bad, I sat back down and looked at the bottoms of my feet and they looked like burnt toast. It was a little sore to walk for a few days after that.

I no longer worry about lightning when I'm hiking.

When I say I don't mess around with lightning, I mean it, including at home. I unplug everything, I don't talk on the phone, I don't use the bathroom, wash my hands etc etc. I wait for the storm to pass and then go about my day. I have family members who have been struck by lightning inside their house while doing certain things (like talking on the phone and....using the toilet....). But in the end, I still feel safer inside a a reinforced structure then outside soaking wet with tall trees all around me. Not my idea of a good time.

grouseking

 

[SAR-EMT40]

Keith -

And while we're on the topic of correcting Doug (which is damn rare) - the speed of sound at 1000/sec is usually qualified by saying that measurement is at sea level, where air is the most dense, and therefore sound travels slightly faster there (if I remember my physics correctly).

Doug - am I right? How does the speed of sound compare at, say 5K? or 10K?

Kevin

You are correct. The speed of sound varies with not only altitude but temperature as well. it doesn't really change all that much for changes in reasonable altitudes.

At seal level the speed of sound is about:761MPH
at 5000 feet 748MPH
at 10000 feet 734MPH


Keith

 

[DougPaul]

Correcting a typo (brain burp) on Dougs part. I know he knows the correct number, and units.

186000 Miles per second

Everything else in his post, as usual, is correct.

Keith

Just put that in to see if you are actually reading the post...

Actually, thanks. I try, but you can't win them all.

Original corrected.

Doug

 

[DougPaul]

Keith -

And while we're on the topic of correcting Doug (which is damn rare) - the speed of sound at 1000/sec is usually qualified by saying that measurement is at sea level, where air is the most dense, and therefore sound travels slightly faster there (if I remember my physics correctly).

Doug - am I right? How does the speed of sound compare at, say 5K? or 10K?

Sorry Kevin , the speed of sound is proportional to the square root of the absolute temp. Keith was close... (Once upon a time, I had to write a flight simulator program from scratch. Had to learn about some of these things...)

So the colder temps generally found at higher altitudes slow the speed of sound. The pressure isn't a factor until there isn't enough to transmit the sound.

Keith's table is probably accurate for "standard" temps at the altitudes (haven't checked the numbers myself). The sea level speed assumes some standard temp and the others probably assume a some standard temp profile. (I had to learn about this too for the simulator.)

I don't remember the details, but my simulator program thinks that it does:

Standard temp profile up to 29500 ft:
temp = 287 -.002*alt;
..... temp = deg K (K = C+273, 287K = 14C)
..... alt = altitude in feet
(From some forgotten aircraft or aerodynamics manual.)

Speed of sound:
sos=1087*sqrt(temp/293);
..... sos=speed of sound in ft/sec (1 ft/sec = .682 mph)
..... temp=temp in deg K

Doug

 

[Stan]

All equations aside, lightning can take place faster than a New York minute. My personal rules for lightning storms:

1. Be aware of changing weather conditions and get below treeline before a storm is imminent ... even if it means doubling back later on.
2. Don't be the highest point around (hike with tall people?). Be at least half the height away from the tallest object near you.
3. Stay out of rivlets; they can conduct a strike to anything in the path.
4. It may be tempting to take shelter under an overhanging rock but they can conduct a strike directly to the highest point below them.
5. Get low and insulate yourself from the ground if at all possible. Get away from metal like poles and backback frames.
6. As difficult as it may be to separate from the mutual comfort and support of others during a storm, spread out. At least if lightning does strike someone it won't disable a team or an entire group. Pete Hickey experience, as well as many others who survived strikes, aside, lightning can kill or do permanent damage

The only time I came close to being hit was being in a room in which lightning bounced off a tree to a dormer. The explosion is powerful, loud, damaging and unforgetable.

 

[Jeff-B]

...when the lighting strikes...

ah, the last good Aerosmith song...

Well, actually - it was my hike on Saturday.
In spite all my alledged experience and reading of everything, Tuco and found ourselves caught in quite a t-storm about halfway down the Gale River Trail on Saturday afternoon.
We just kept moving down and out as fast as we could, but were not totally sure of what the best plan would have been after getting caught...
The storm was pretty rough and violent, but I never thought it was too close....maybe 3 seconds at the worst between lighting and thunderclaps...
We just kept moving except for once when it seemed to close and we stepped off the trail under some better cover and off the trail/river bed for a couple of minutes...


Any thoughts on the best thing to do? We were pretty much just trying to get out of it as fast as possbile and figured the higher trees were more likely targets than us - but these could have been famous last words....

When this particular cell hit, we were already down in the parking lot at Garfield, not more than 1 mile from you!
It was SCARY big cloud to ground lightning all around us.

Word of advice: 3 second delay is as good as NO delay....that storm was on you!
Seroiusly, I got in the car and stayed off the ground for fear of impact.

What would "I have done" in your case? I don't know, maybe just what you did do...KEEP MOVING, but stay separated from each other as someone stated.
Its times like this I wish I could toss my trekking poles.

 

[sapblatt]

What would "I have done" in your case? I don't know, maybe just what you did do...KEEP MOVING, but stay separated from each other as someone stated.
Its times like this I wish I could toss my trekking poles.

Yeah - it is such a tough call - I was very glad we went in this direction as our original plan would have had us on the ridge at that time...

The poles were a bit troubling...I was not going to ditch them (pretty dumb thoug - I will not sacrifice a $70 pair of poles with my life!?) I figured attaching them to my pack would make them even more elevated...

I agree that 3 seconds and 1 second don't mean much...I think I told myself that to keep from panicing.

I think the only thing I would have done differently next time is that I would have stayed a bit off the trail and out of the stream that was the trail...otherwise, getting out fast seemed to be the best plan.

 

[DougPaul]

Its times like this I wish I could toss my trekking poles.

Just shrink them to minimum length and carry them as out of the way as is convient (eg in your hand or on your pack).

If you are stopped, it wouldn't hurt to put them a short distance away.

The electrical effect of a metal pole is primarily a function of its length unless it is touching something else. Continuing to use the pole for walking may be a bad idea--it would be another contact point for ground currents. A leg-to arm shock is also more dangerous than a leg-to-leg shock because it goes through the heart region.

Doug

 

[SAR-EMT40]

Sorry Kevin , the speed of sound is proportional to the square root of the absolute temp. Keith was close... (Once upon a time, I had to write a flight simulator program from scratch. Had to learn about some of these things...)

So the colder temps generally found at higher altitudes slow the speed of sound. The pressure isn't a factor until there isn't enough to transmit the sound.

Keith's table is probably accurate for "standard" temps at the altitudes (haven't checked the numbers myself). The sea level speed assumes some standard temp and the others probably assume a some standard temp profile. (I had to learn about this too for the simulator.)

I don't remember the details, but my simulator program thinks that it does:

Standard temp profile up to 29500 ft:
temp = 287 -.002*alt;
..... temp = deg K (K = C+273, 287K = 14C)
..... alt = altitude in feet
(From some forgotten aircraft or aerodynamics manual.)

Speed of sound:
sos=1087*sqrt(temp/293);
..... sos=speed of sound in ft/sec (1 ft/sec = .682 mph)
..... temp=temp in deg K

Doug

Warning: some science below.


Not exactly. As I remember Doug, I think you are using the ideal gas law. Now this is OK but it ignores the pressure changes, but they are there. Ignoring it is OK because the gas we are talking about is air and air, while not truly an ideal gas (no gas is ideal) it is close enough to use the ideal gas equation in most instances. Considering the gas to be ideal and forgetting to include the changes do to pressure because of altitude is OK in this case because the contributions of altitude is much much smaller than the contributions due to temperature.

Short answer is what Doug has done is perfectly reasonable in his simulator, longer answer is that altitude does affect the speed but its contribution is small enough that most times its contribution can be ignored. Like any good engineer Doug went for the simplier equation that gives engineering answers that are perfectly respectable considering what needed to be done.

Now all of this was from my fluids and gases classes and that was a long time ago. Its what I remember but I have already established that my memory isn't what it used to be. What I was stating was based on the full equations relating pressures/temperature etc. There are times, like this, when you can get away with the simplification of the gas equation by using the ideal gas law, and this is one of those times. Hope this makes sense? If I have made some mistake then let me know.

I know we have strayed somewhat from strict outdoor stuff but we are using words like altitude, temperature, so hopefully this is still OK.

Keith

 

[LittleBear]

Sapblatt wrote:

I agree that 3 seconds and 1 second don't mean much...I think I told myself that to keep from panicing.

Of course, lightning can strike up to 10 miles away from where the storm is situated.

 

[DougPaul]

Sapblatt wrote:
Of course, lightning can strike up to 10 miles away from where the storm is situated.

Lightning can also strike out of a clear blue sky, but both are rare occurrances.

Doug