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#406927 - 07/07/15 09:54 PM Walking - Lightning
Harland Online   content
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Registered: 29/04/05
Posts: 1306
Loc: North Yorkshire
In view of the recent fatalities I thought that I should recheck what I should do in similar circumstances. There will no doubt be other guidance that can be found on the web but I thought that others may wish to read the following.

The Danger of Lightning - Advice on Staying Safe

Even though the chances of being struck by lightning are small, high on a mountain is a dangerous place to be during a storm. The advice below is taken from the book 'Hillwalking', published by Mountain Leader Training UK, and was reproduced by The Mountaineering Council of Scotland on their website with their permission.

Lightning strikes rarely come as a 'bolt out of the blue'. Towering clouds build up as unstable air spirals upwards and condenses, giving a good warning to the observant walker. As a storm approaches, its location can be estimated by noting the difference in time between lightning flashes and the rumble of thunder. The light appears almost simultaneously, while sound travels at a speed of 1 km per 3 seconds. A six-second delay therefore means that the storm is about two kilometres away.

Lightning strikes are quite frequent on summits and other projections such as pinnacles, because lightning takes the shortest route to earth. These are the areas of greatest risk, and at the first sign of an approaching lightning storm, the party should evacuate to a safer area. Scrambling terrain is particularly hazardous in lightning, and difficult to escape from quickly. A strike could easily knock somebody from his or her footing. Retreat should definitely not be by abseil, because the wet rope provides an excellent conductor. Steep or exposed ground should therefore be avoided if storms are forecast, or at least be pre-empted by a very early start and finish.

Direct lightning strikes on people are relatively rare, but can be extremely violent and often fatal. More common is a partial strike, either through induction from an adjacent or nearby conductor, or through the ground as the earth currents dissipate outwards. The actual power of the stroke is a combination of the current and the contact time.

A projection such as a pinnacle or post acts as a lightning conductor that services an area with a radius corresponding approximately to its own height. This means that the area within this circumference is a relatively safe place to wait because the projection will deflect lightning strikes on itself.

Sheltering under an overhang or a tree is a hazardous course of action because a lightning strike will bridge the gap taking the most economical route, in this case through the people and into the ground. It is much safer to sit out in the open wearing waterproofs.

A walking party sitting out a lightning storm should ideally crouch or sit upright on top of insulating material such as rucksacks and sleeping mats. Hands should be kept on knees rather than touching the ground. Metal items of equipment do not significantly increase the risk of attracting a strike, but if they start to hum and spark, it would be wise to accept the hint and lay them to one side until the storm passes.
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Pennine Way 2005&2014; C2C 2006; SWCP 2007; WHW 2008; GGW 2008; Dales Way 2011; Clev.W 2012; Yorkshire W.W. 2012; Offa's Dyke 2013; Peddars Way & Norfolk Coast Path 2014; Pembrokeshire Coast Path 2015: Land's End to John o'Groats in stages 2018.

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#406930 - 08/07/15 01:01 PM Re: Walking - Lightning [Re: Harland]
lightweightmick Online   confused
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Registered: 18/11/04
Posts: 1690
Loc: North Derbyshire UK
Good advice - timely share - do you have a link to the recent incident?
cheers
mick
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#406931 - 08/07/15 02:23 PM Re: Walking - Lightning [Re: Harland]
Harland Online   content
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Registered: 29/04/05
Posts: 1306
Loc: North Yorkshire
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Pennine Way 2005&2014; C2C 2006; SWCP 2007; WHW 2008; GGW 2008; Dales Way 2011; Clev.W 2012; Yorkshire W.W. 2012; Offa's Dyke 2013; Peddars Way & Norfolk Coast Path 2014; Pembrokeshire Coast Path 2015: Land's End to John o'Groats in stages 2018.

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#406935 - 10/07/15 01:27 AM Re: Walking - Lightning [Re: Harland]
Geo Offline
Full Member

Registered: 19/09/05
Posts: 398
Loc: Oamaru, New Zealand
Not quite sure I get this part of their advice. (seems contradictory to me but maybe I'm missing something!)

A projection such as a pinnacle or post acts as a lightning conductor that services an area with a radius corresponding approximately to its own height. This means that the area within this circumference is a relatively safe place to wait because the projection will deflect lightning strikes on itself.

then goes on to say...

Sheltering under an overhang or a tree is a hazardous course of action because a lightning strike will bridge the gap taking the most economical route, in this case through the people and into the ground.

I would have thought sitting in the vicinity of a post would be similar to sitting in the vicinity of a tree and thus inviting a 'deflected' strike. (with lightning bridgeing the gap and taking the most economical route) I'm wondering if they meant to say 'This means that the area OUTSIDE this circumference is a relatively safe place to wait because the projection will deflect lightning strikes on itself."
If that's the case, then quite a serious and potentially fatal difference in meaning.
Any thoughts?

.
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#406936 - 10/07/15 09:45 AM Re: Walking - Lightning [Re: Geo]
Harland Online   content
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Registered: 29/04/05
Posts: 1306
Loc: North Yorkshire
I did think about this as well. I assumed that it meant if you are within the circumference area then you wouldn't get a direct strike but if you moved further away outside of this area then the lightning could/would strike you directly. Standing directly beside the trunk of a tree I assumed would not be too bright.

However if anyone can find good advice from elsewhere then please post it as it may help prevent a serious problem.
_________________________
Pennine Way 2005&2014; C2C 2006; SWCP 2007; WHW 2008; GGW 2008; Dales Way 2011; Clev.W 2012; Yorkshire W.W. 2012; Offa's Dyke 2013; Peddars Way & Norfolk Coast Path 2014; Pembrokeshire Coast Path 2015: Land's End to John o'Groats in stages 2018.

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#406937 - 10/07/15 10:27 AM Re: Walking - Lightning [Re: Harland]
Geo Offline
Full Member

Registered: 19/09/05
Posts: 398
Loc: Oamaru, New Zealand
I would say lightning generally will be attracted to the tallest object in the vicinity, eg. a tree or post. So keeping away from a post and lower than the post is the best bet - not as they say next to it being safest.
The NOAA (National Oceanic and Atmospheric Administration) advises to keep away from trees AND poles which is what I would have thought. see http://www.erh.noaa.gov/box/lightning.html
(Just as an aside, anyone who uses hiking poles, it's a good idea not to have them stowed on your pack and sticking up in dodgey weather!) crazy
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#406938 - 10/07/15 09:52 PM Re: Walking - Lightning [Re: Harland]
Harland Online   content
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Registered: 29/04/05
Posts: 1306
Loc: North Yorkshire
The Mountaineering Council of Scotland web site, where I copied the above advice, showing a couple of pictures seems to make this clearer (hopefully!)

http://www.mcofs.org.uk/lightning.asp
_________________________
Pennine Way 2005&2014; C2C 2006; SWCP 2007; WHW 2008; GGW 2008; Dales Way 2011; Clev.W 2012; Yorkshire W.W. 2012; Offa's Dyke 2013; Peddars Way & Norfolk Coast Path 2014; Pembrokeshire Coast Path 2015: Land's End to John o'Groats in stages 2018.

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#406939 - 10/07/15 10:27 PM Re: Walking - Lightning [Re: Harland]
Geo Offline
Full Member

Registered: 19/09/05
Posts: 398
Loc: Oamaru, New Zealand
Hi Harland,
Just had a look at the link.
I can agree with the article as it's written in the link.
What had me questioning was that in the 5th paragraph of your original post there seems to be the words 'or post' added ie 'A projection such as a pinnacle OR POST'
Maybe it had been brought to their attention and they've corrected it since the time you copied the article!
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Dances With Marmots

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#406940 - 11/07/15 09:46 AM Re: Walking - Lightning [Re: Harland]
Harland Online   content
Full Member

Registered: 29/04/05
Posts: 1306
Loc: North Yorkshire
They must have changed it as I copied it (i.e. cut and pasted not retyped) on the day I posted the article. Good that you questioned the message as it will hopefully have reinforced peoples understanding, including mine!
_________________________
Pennine Way 2005&2014; C2C 2006; SWCP 2007; WHW 2008; GGW 2008; Dales Way 2011; Clev.W 2012; Yorkshire W.W. 2012; Offa's Dyke 2013; Peddars Way & Norfolk Coast Path 2014; Pembrokeshire Coast Path 2015: Land's End to John o'Groats in stages 2018.

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#406941 - 12/07/15 11:24 AM Re: Walking - Lightning [Re: Harland]
Geo Offline
Full Member

Registered: 19/09/05
Posts: 398
Loc: Oamaru, New Zealand
I guess we're fairly lucky (in NZ & UK) in that we don't experience 'regular' thunderstorms. In some parts of the US afternoon thunderstorms are common at certain periods of the year. You might find this article on lightning behaviour by John Gookin, Curriculum & Research Manager of The National Outdoor Leadership School to be informative. Lightning Behaviour
Gookin is American - but lightning is universal! smile
Been caught out in a few thunderstorms over the years but luckily nothing disasterous!
A few figures I came across for the UK were that about 30-60 people are struck by lightning each year of whom, on average, three may be killed. (I'm guessing that these would typically be outdoor workers who spend a high percentage of their time out in the open rather than hikers) There are around 300,000 ground strikes by lightning every year in Britain. On average (based on a ten-year period), this means that someone is struck once every 6,000 strikes and someone killed once every 100,000 strikes. A 'thunderstorm day' may produce up to 10,000 ground strikes. crazy

Cheers, Geo.
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#406942 - 12/07/15 02:00 PM Re: Walking - Lightning [Re: Harland]
Harland Online   content
Full Member

Registered: 29/04/05
Posts: 1306
Loc: North Yorkshire
I see from this article:-
"Since side flash emanates from trees or other tall objects struck by lightning, never seek shelter near a tree, other tall object, or tall vertical surface. Side flash is one of the reasons that the “cone of protection” is a myth”.
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Pennine Way 2005&2014; C2C 2006; SWCP 2007; WHW 2008; GGW 2008; Dales Way 2011; Clev.W 2012; Yorkshire W.W. 2012; Offa's Dyke 2013; Peddars Way & Norfolk Coast Path 2014; Pembrokeshire Coast Path 2015: Land's End to John o'Groats in stages 2018.

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#406943 - 12/07/15 10:39 PM Re: Walking - Lightning [Re: Harland]
Geo Offline
Full Member

Registered: 19/09/05
Posts: 398
Loc: Oamaru, New Zealand
Originally Posted By: Harland
I see from this article:-
"Since side flash emanates from trees or other tall objects struck by lightning, never seek shelter near a tree, other tall object, or tall vertical surface. Side flash is one of the reasons that the “cone of protection” is a myth”.

Yes, thought there were some interesting points in the article. The dangers of being near a fenceline (pic of all the dead cows!) was one that I hadn't considered before reading the article.
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Dances With Marmots

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#406944 - 13/07/15 09:30 AM Re: Walking - Lightning [Re: Harland]
Harland Online   content
Full Member

Registered: 29/04/05
Posts: 1306
Loc: North Yorkshire
I emailed the National Trails to see if they had any advice. They suggested the Royal Society for the Prevention of Accidents and The Ramblers Association web sites, see the following:-

http://www.rospa.com/leisure-safety/advice/lightning/

and

http://www.ramblers.org.uk/advice/safety/thunder-and-lightning.aspx

Trust that this will make us, including me, think more carefully in future. Previously I continued to walk as the ground was very wet and muddy and I thought I would be OK - pretty stupid really!
_________________________
Pennine Way 2005&2014; C2C 2006; SWCP 2007; WHW 2008; GGW 2008; Dales Way 2011; Clev.W 2012; Yorkshire W.W. 2012; Offa's Dyke 2013; Peddars Way & Norfolk Coast Path 2014; Pembrokeshire Coast Path 2015: Land's End to John o'Groats in stages 2018.

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