Lightning Questions

Question: I was wondering about what happens when lightning hits the water right next to you, "like on a lake", what can happen. Does it even hit water? If not, what if it hits a metal pole directly sticking out of the water like just 6 feet away or so from a person or a wooden piling etc.. ? See, I do a lot of outdoor water activities here in FL and seem to always get caught up in electrical storms. Been pretty worried when taking the boat out of water during electrical storms when near that metal boat trailer. Would love to just know more about what lightning can do? Like traveling through water etc..? Any information would be greatly appreciated.

Answer: Although atmospheric electricity is one the oldest of the atmospheric sciences, it is also one of the least mature. Two areas in which we are especially ignorant are 'ball lightning' and 'how lightning behaves when it hits water'.
 
First of all, lightning certainly does hit water. There is a wealth of photographic evidence that shows this.
 
We hypothesize that lightning hitting water spreads out mostly along the surface of the water and the more electrically conductive the water is, e.g. salt water, the more it stays near the surface. How far it spreads out along water and remains a danger is even more uncertain. Lightning striking ground can still be dangerous over 100 feet from where it struck. Some believe lightning will go even further in water, because it's a conductor. But lightning in ground often spreads out in 'ground streamers', quasi-radial tendrils of electricity, which allows it to go farther than if it was dissipating uniforming. Some believe lightning is less likely to form these streamers in water, dissipating more uniformly. So the total area affected may be larger than on land, because water is a better conductor, but the distance it remains dangerous may be less, since it may not form ground (sic) streamers. However, I'm extremely confident that "6 feet to the post" is insanely inadequate for safety. At that distance, you're in danger of a lightning 'side flash' from the post through the air to you, even before it finds the water. General lightning safety guidance uses 6 miles as a reasonable compromise between safety and lifestyle impact.


Metal does not attract lightning. When thunderstorms are nearby, there are three main factors determining what gets struck, the objects: 1) height relative to other objects, 2) isolation, and 3) pointiness. But the path of least resistance (technically, impendence) from the cloud to the ground can be very convoluted, so lightning is more likely to strike tall isolated pointy objects, but there are no guarantees. However, large long metal objects are still an especial lighting hazard because if they are hit coincidentally, they can carry the dangerous electricity a long distance. Think of crowds of sports fans pressed against a long metal fence or railing with thunderstorms nearby -- scary!
 
In Florida, water related activities (swimming, boating, and fishing) is the #2 activity for lightning casualties. You also mentioned loading the boat with lightning nearby. The lightning casualty stories are replete with events where people were within minutes of getting to a reasonably safe location (large fully enclosed building with wiring and plumbing, or a vehicle with a solid metal roof and sides). If they had started for shelter just a little sooner, or hadn't stopped to load the boat or pack their picnic or whatever, they likely would've avoided the casualty. When you consider the threat to life and the more frequent life-long debilitating injuries lightning causes, it is smart to obey the lightning safety guidelines. 

A wealth of good lightning safety information is available at
www.lightningsafety.noaa.gov, https://www.patrick.af.mil/45og/45ws/lightningsafety. The latter website has links to 2 excellent websites on lightning and boating.
 
Since you are in Florida, I'll contact you directly to offer lightning safety training.
 
Bottom-line: lightning and water related activities are a bad combination. Please learn more about lightning safety and avoid becoming a statistic.
 
Enjoy! Lightning Safety: https://www.patrick.af.mil/45og/45ws/LightningSafety

William P. Roeder, 45 WS/SYR
1201 Edward H. White II St., MS 7302
Patrick AFB, FL 32925-3238
william.roeder@patrick.af.mil
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