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Posted by Bill S on September 11, 2006 at 7:48:36 pm EDT
In reply to Thunderstorms posted by Dave S on September 11, 2006 at 6:38:42 pm EDT

There is a good National Weather Service web page on this, which you can get to through the regional NWS office for your area. Do a google search for "National Weather Service lightning" and it will give you the link through your closest office. Or directly to http://www.lightningsafety.noaa.gov/

Basically, you don't want to be the highest object in the vicinity, close to the highest object (stay away from tall trees), or on something like a peak or ridgeline. If you are in a boat on a lake, get to shore as soon as possible. Getting into the water doesn't help, because your head will still be the highest object on the water surface.

You can get into a large grove of trees in a valley, making sure you are near the shorter trees. Bottom of a gully is poor, since that makes a natural current conduit. Also, do not get under a rock overhang or into a cave - in the overhang or cave entrance, you partly fill the spark gap, making a good path. Inside a cave, the current may travel through the cracks, which will then find you.

There is a rule about ground currents ("splatter") that takes note of the fact that if you look at the ground around a tree (or more commonly, the flag at the hole on a golf course - golfers get hit by lightning more than just about any activity) that has been hit, you usually see a spiderweb of burn marks. The rule has to do with a 45 degree sightline. It is better illustrated on the NWS pages than you can describe it in words.

A good description is given in Mountaineering Freedom of the Hills - a book you really need to get. This is one of several books published by the Seattle Mountaineers. It gives lots of info about general backpacking and outdoor activities (and has been recommended to you and lots of others here before). The Mountaineers Press also has a good little book on lightning. Much better than anyone can put in a post on the Web.

Replies

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• Re: Thunderstorms - Dave S 20:13:42 09/11/2006
  • Re: Thunderstorms - Tom D 02:34:21 09/12/2006
    • Re: Thunderstorms - Chumango 06:18:48 09/12/2006
      • Re: Thunderstorms - Tom D 01:02:58 09/13/2006
        • Re: Thunderstorms - lambertiana 08:48:51 09/13/2006
      • Re: Thunderstorms - Bill S 16:49:25 09/12/2006
        • Re: Thunderstorms - Chumango 19:57:34 09/12/2006
          • Re: Thunderstorms - Bill S 00:48:36 09/13/2006
        • Re: Thunderstorms - Dave S 17:07:18 09/12/2006
      • Re: Thunderstorms - Ed G 06:41:14 09/12/2006
        • Re: Thunderstorms - Bill S 16:33:31 09/12/2006
        • Re: Thunderstorms - Chumango 07:19:20 09/12/2006
          • Re: Thunderstorms - Dave S 11:23:04 09/12/2006
            • Re: Thunderstorms - Ed G 11:53:10 09/12/2006

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