40% chance of thunderstorms.Safe to swim?

[summerbreeze]

My townhouse has a nice pool; chainlink fence, concrete apron with steel tables and chairs. Around here we often have hazy or partly-cloudy days with temperatures in the 80’s or 90’s. Seems like great weather to swim, but is it safe to use the pool when thunderstorms are predicted, even if there aren’t any dark clouds in the sky at the moment?

[Q.E.D]

When thunderstorms are in the area there’s always a danger of being struck. There have been cases of people being hit by lighting, seemingly out of a clear blue sky, from storms as far off as tweny miles away. Nevertheless, the risk is fairly small until the storms are basically on top of you.

[clairobscur]

Sorry to somehow hijacking the thread, but I’m not sure to understand the issue. Is it particularily hazardous to swin during a thunderstorm? I mean, are you for some reason more likely to be struck by lightning in a pool rather than, say when standing on the ground???

[Q.E.D]

Actually, depsite the aversion most people have to mixing electricity and water, you are less likely to be struck while in the water. If the lightning should strike the water itself, rather than you, you will probably feel it, but very little current will pass through your body; not nearly enough to harm you. The thunder might not do you much good if you have a weak heart, though.

[Shalmanese]

If I were you, I would be in the water rather than leaning against that chain-link fence. Sounds like thats got more chance of being struck.

[summerbreeze]

Guess that’s what I’m thinking of, y’all, rather than actually being in the pool. Sitting near the fence, on metal chairs, at metal tables.

What concerns me is what Q.E.D. addressed – lightning out of a clear blue sky when thunderstorms are in the area. I hate to waste a day off doing stuff indoors when I could have been at the pool just because there were thunderstorm warnings that never materialized.

[Early_Out]

There’s a big difference between a forecast that says there’s a 40% chance of thunderstorms and a thunderstorm watch and a thunderstorm warning.

The first is simply a forecast that says that there’s a chance that conditions might evolve, sometime during the forecast period, that will favor the development of thunderstorms. No real cause for concern, and certainly not enough to make you cancel your pool or golfing plans. A thunderstorm watch means that there are actually atmospheric conditions, right now, that favor the development of thunderstorms. No actual thunderstorms yet, but the atmosphere is primed and ready. Probably time to rethink your plans. A thunderstorm warning means that there are currently thunderstorms in the area. Time to head for shelter.

[jacksen9]

I was a lifeguard for many, many years. I had to frequently update certifications and get more training. I have never, ever heard that you are safer in the water during a thunderstorm or if conditions are right for lightning. I just googled pools, water, lightning. All the information I found in my quick search stated that people should get off beaches, pools, lakes, large open areas, and seek shelter indoors. I do not think you would be safer in the water. Well, I suppose if you had to choose between standing on a three meter diving board or a ladder and a swimming pool, the pool would be safer.

[Q.E.D]

Your safety in a thunderstorm, all things being equal, is directly related to your height above ground relative to objects around you (it’s a probability thing–shorter objects can get struck, but taller objects are more likely to). At the shore, with very few trees or tall structures around, you are most likely to be the tallest object (other beachgoers notwithstanding). In the water, however, you’re relatively safe, since only your head is above water (assuming you are in water greater than wading depth). As I said before, if lightning actually hits the water, but not you, you won’t get fried, since all the points around your body will be more or less at the same potential, and therefore little or no current will flow through you.

[lite]

HowStuffWorks - Learn How Everything Works!

Right now the "how lightning works’ is on the front page. It explains how lightning can travel for miles from the initial strike, using a phenom called “stepping”.

[jacksen9]

*Originally posted by Q.E.D. *
** As I said before, if lightning actually hits the water, but not you, you won’t get fried, since all the points around your body will be more or less at the same potential, and therefore little or no current will flow through you. **

I find this to be difficult to accept. Isn’t water a strong conductor of electricity? Why would Lifeguard training and water safety programs teach and promote the idea that if there are thunderstorms and conditions right for lightning, people should get the hell out of the water? I would like to see a cite that explains how swimmers are safer if they stay in the water during lightning strikes.

[lite]

because water conducts voltage, it doesn’t centralize it. Biggerthe pool of water, the less electricity

[jacksen9]

*Originally posted by lite *
**because water conducts voltage, it doesn’t centralize it. Biggerthe pool of water, the less electricity **

Oh well then. Let’s all go swimming during a lightning storm. We will be safe and it will be fun. Right. Right. Hmm.

[voltaire]

Ron Holle, research meteorologist, NOAA National Severe Storms Laboratory, Norman, Okla. has this to say about lightning and water:

"Large numbers of lightning flashes strike oceans, lakes, rivers, and ponds. If there is nothing protruding higher than a body of water or flat ground, then a flat surface is hit.

The area of a swimming pool is small, so it’s not usually directly hit. However, the area affecting a pool is quite large. This area includes the surrounding power and telephone lines, and the plumbing around the pool and inside the bathhouse and other structures. These are usually unsafe places during a thunderstorm because the current from a lightning strike will
travel easily through the standing water, showers and other plumbing. Since the pump, lights and other facilities have power lines linked to the plumbing, a hit to any part of a pool complex can affect all of it.

Water does not “attract” lightning. It does, however, conduct current very well. It’s not clear how far lightning travels through water. People have been killed or injured by direct or indirect strikes while in or on the water, boats, docks, piers, surf, surfboards, canoes, while fishing, and so on. In most cases, it appears that the strike was within a few tens of yards of the person. But the current can extend farther through plumbing or wiring so the distance of influence can be greater.

The current in a lightning bolt is as high as 30,000 amperes — about ten times more than ordinary house current.It’s easy to see how this much electricity is deadly. Fortunately, many lightning victims aren’t hit directly, of all the charge doesn’t go through them. This is why about six out of every seven persons hit by lightning survive, although sometimes with serious injuries and lasting ill effects.

Lightning will often hit something, such as a tree, a wire fence or a boat mast. Most of the electricity flows through the object that it hits, but some jumps to hit a person or people. This is called a ‘side flash’. Such side flashes have killed people talking on the telephone or taking a shower inside otherwise safe buildings, following through phone lines or water pipes after hitting the ground. People are also sometimes injures when lightning hits the ground and follows it to where they are standing.

Lightning can affect all parts of the body, but the usual cause of deaths is heart stoppage. The electrical charge disrupts the heart’s rhythm, stopping it. Usually, however, the heart will quickly resume beating. The electricity is more likely to paralyze the brain’s respiratory center. The victim will die from lack of oxygen unless someone nearby can quickly perform artificial respiration to get the victim’s breathing going again. This may have to continue for hours before the victim begins to breath normally.

A Lightning Safety Group, which met at the 1998 American Meteorolgical Society convention to update safety recommendations, noted in it’s report: “Generally speaking, if an individual can see lightning and/or hear thunder, he or she is already at risk. Louder or more frequent thunder indicates that lightning activity is approaching, increasing the risk for lightning injury or death.”

The report also notes that “many lightning casualties occur in the beginning, as the storm approaches — Also, many lightning casualties occur after the perceived threat has passed.” In fact, the danger can persist as long as thirty minutes after the storm has passed and the last thunder is heard.

Lightning always comes from a thunderstorm cloud, but has been known to hit as far as 20 milesfrom the nearest cloud, far from the storm’s rain. This is why the group says seeing just one lightning bolt or hearing one clap of thunder should be a warning to get into a safe place.

http://scuba-doc.com/lightdive.htm

• A significant number of lightning victims were in the vicinity of water in
  Florida (Duclos et al. 1990; Holle et al. 1993).

http://www.uic.edu/labs/lightninginjury/holle30yrs.htm

[voltaire]

When finding the above sources, I was really looking for something about the two boys in my area (South Florida) who were killed by lightning while swimming in a pool a couple years ago. I give up, you’ll just have to take my word for it. But I believe the info above should be enough to convince most rational people to get everyone the hell out of the pool during an electrical storm.

I, having lived in South Florida most of my life, have been almost hit by lightning twice. Altough you can never be completely safe, I’ve learned to always take at least the minimum precautions. Getting out of the pool would DEFINITELY be a BARE MINIMUM precaution.

[Q.E.D]

I have to doubt a source which says:

The current in a lightning bolt is as high as 30,000 amperes — about ten times more than ordinary house current.

the maximum service available to most residences is 200 amps, not even remotely close to 3,000. And I can find no cite for a person actually being killed by an indirect strike on water in which they were swimming. Nor can I find one for a person being killed in the shower, though I have found a few for telephone deaths.

[El_Zagna]

I don’t think that Q.E.D. is suggesting that we all jump in the pool to protect ourselves from lightning, but rather that there are a lot worse places to be, for example, sitting on a metal chair, at a metal table, underneath an umbrella with a metal pole.

[Q.E.D]

Exactly. Anywhere there is at least some risk, even indoors. If I had a choice between waiting out a storm in the pool and hanging out on the roof, I’ll take the pool.

[Reeder]

*Originally posted by lite *
**because water conducts voltage, it doesn’t centralize it. Biggerthe pool of water, the less electricity **

Just a bit of a nitpick…water does not conduct electricity. The impurities in the water do.

[summerbreeze]

Not only will I never go to the pool again, I may never take a bath!

How about if I throw all the metal chairs and tables into the pool and stay out myself?