Why You Should Never Swim During A Thunderstorm

One of the most dangerous things you can do during a thunderstorm is to go swimming. Either in your swimming pool or on the beach or river. Bolts of lightning usually accompany storms and you can easily get electrocuted.

The best thing to do is to stay indoors. Water is a good conductor of electricity, and salty water is the best conductor. Stay away from oceans, lakes and even outdoor swimming pools.

Just how dangerous is it? How safe is your location from the approaching storm? What if lightning strikes when I am inside the pool? Are there any channels that alert people when a raging storm is approaching? These are some of the questions we will be answering, and backing them by facts and figures. Because every danger has a science behind it and possible solutions.

How Powerful Are Thunderstorms

Thunderstorms are usually accompanied by lightning; that’s why you see a flash of light before hearing the sound. This is because light travels faster than sound. Lightning, in simple terms, is electrostatic discharge.

It occurs when there is a static charge between the clouds and the ground, or between two clouds. These static charges can be powerful. This feature shows why lightning travels in any possible direction. This is why flash is very dangerous. The worst part is yet to come.

The number of volts in a lightning bout or strike can be more than 100 million volts. Yes, this charge is enough to turn any solid matter into gas. Don’t risk it. The temperature around the lightning bolt is around 50000 degrees Fahrenheit.

It only takes a fraction of a second for lightning to strike any area. The worst place to be found when lightning strikes, is in any body of water. We are not oblivious of the fact that lightning can strike someone under a tree. But the bottom line is, when it rains, seek refuge indoors.

When Lightning Strikes the Water

If lightning is this powerful, why are the fish not electrocuted? Good question. Flash mostly occurs in the ocean area. Most people can concur with this issue. Now back to the subject.

When lightning strikes the surface of any water body, the charges are not conducted deep enough. They just spread on the surface of the water body. They spread horizontally as opposed to vertically.

The spread of the charges depends on the voltage of the lightning strike. Nobody knows how this happens, because it is tough to research on lightning strikes. Otherwise, after a lightning strike, we would see a dozen fish on the water surface as a result of electrocution.

What makes it even more dangerous, is the amount of sound it produces. If lightning strikes nearby, also if you are out of the current travel zone. You can go deaf; the amount of noise the thunderstorm produces is close to 250 decibels. This high-frequency sound is enough to make you go deaf. The best thing to do is to avoid swimming during a thunderstorm.

If the Storm Happens Unexpectedly

There are some instances when clouds gather fast and within no time. Lightning strikes without notice. If lightning strikes nearby, while you are in the water, the best thing to do is to move out of the water as fast as you can.

Any delay might cost you your life. If you are on the beach, run very fast to any shelter. If you were swimming some distance from the beach, and you think you cannot make it in time to the shore – a good option is to dive deep if you feel that you are in the lethal strike zone. It might not be the worst idea.

If you can hold your breath for some seconds, then you are right. Because earlier, I stated that lightning only takes a fraction of a second to strike. The lethal current disperses on the surface of the water instantly.

The objective here is to stay alive. So when lightning strikes nearby while you are in the water, there are two options. You either dive deep for a few seconds or get out of the pool as quickly as you can. Otherwise, you are a dead man.

Safe Distance

The approximate distance that a bolt of lightning can strike from the charging clouds is 10 miles. That’s according to some researchers. Whether or not it’s raining on you, you are at risk of getting struck.

There are two options here, you either get out of the pool upon hearing the first rumble of thunder, or stick around until its close enough. The recommended option is to get out of the pool, as soon as you hear the first rumble. This option is the safest.

The second option is not a bad idea. You must have someone on the lookout to help with the timing process I am about to share with you.

There is a 30-30 rule. If you hear the sound of thunder within 30 seconds, then the lightning has a strike radius of 6 miles. It means that after every 5 seconds, the deadly strike is a mile closer to you. Most of you are still not sure how this works.

Let me re-phrase my words. As soon as the person on the look-out sees a flash of lightning, he/she should turn on the timer. This timer will indicate to you the seconds until you hear the sound of thunder. Because you see the flash, before hearing the rumble. It is worth noting that any mistake in the timing could be fatal. Especially when it is approaching the area you are in.

The safest thing to do is to seek shelter, unless the timer indicates that the sound of thunder is far away more than 20 miles. Before going into the water, you should wait for 30 minutes after the last flash of lightning. Then carry on swimming, but be cautious.

Are There Forecast Services That Alert You If Lightning Is Approaching?

A man listening to his headset with radar  televisions.
Monitoring severe weather.

Yes, there are a few private forecasting services that alert you, especially in lightning prone areas. They provide you with the data after you’ve subscribed to them. There is also the National Lightning Detection Network. They are expensive but worth it.

So if you are a park owner, or a beach guard and maybe parents, you can seek information on these entities, so that everybody is safe. The national Lightning detection Network uses sophisticated instruments to detect and alert people when lightning is close by.

Engineers use a device known as GLM to detect and transmit data. These data are shared with newsrooms. If you can’t subscribe, at least you can turn on the news alert in your phone. Most states transmit this information to the locals.

The safest way to stay out of danger is to leave the pool as soon as you see a lightning flash. Some thunderstorms appear out of the blue before the instruments detect it and transmit the data to newsrooms, and some fatalities will be registered.

It is estimated that the detection systems in the US, monitor about 100,000 thunderstorms every year. So keeping you safe from lightning is an expensive affair for your state.

What If I Am Swimming Indoors?

Let’s be clear. Water does not attract thunderstorms. It is only a medium of current transmission. Most people think that swimming in indoor pools is the solution. No, it isn’t.

The area surrounding the pool is filled with power lines, telephone lines and plumbing materials like pipes and the rest. If lightning strikes the area around your indoor pool, then the indoor swimming pool will not be safe either. The power lines will transmit the sizeable static charge.

At the point where the lines meet with the plumbing pipes, this point will be the transmission point. The pipes will transfer the current to the water. You may suffer electrocution.

That is why talking on a telephone is dangerous during thunderstorms due to the telephone wires conducting the lightning charge. Whenever you hear a lightning strike sound, vacate the swimming pool and seek shelter. Safety is the best protection from electrocution by lightning.

Some may argue that the lightning current will get dispensed and reduce the risk of electrocution. Yes, it is a valid question to ask, considering that the lightning is not striking directly, but through conductors. What the proponents of this argument don’t know, is the amount of current we are talking about here? According to researchers, the amount of current that a lightning strike packs, is about 30,000 Amperes. How does a small indoor pool dispense such a charge? It is lethal, leave the pool during a thunderstorm.

How About Swimming in Fresh Water as Opposed To Salt Water

It’s true that water hardness determines the conductivity of water. But the determining factor here is the amount of current to be conducted. I will not dwell on the current because I already answered it in the previous question. Let us focus on the conductivity of the water source to answer the question.

Freshwater contains fewer anions and cations, and these are responsible for any electrical conduction and transfer of charges. Salty water contains more cations and anions, and this makes it a good conductor of current.

I can conclude that, if lightning current discharges in fresh water, the consequences on you will be severe. If it dissipates in salt water, the results will be worse. This is just a hypothesis. More research is needed on this topic. The bottom line is, lightning does not discriminate the water hardness.

During Tornadoes

An above ground swimming pool that has been destroyed by a tornado.  The area has been leveled.
Swimming pool destroyed during by a tornado.

A tornado is sometimes accompanied by thunderstorms. Swimming during a hurricane is dangerous. A hurricane is generally associated with gales. These are low-pressure zones that generate powerful winds whirling upwards. The winds are strong enough to empty a small pool in seconds.

Hiding underwater is not the best idea during a tornado. Even if you survive the whirling winds, tornadoes wreck buildings and throw debris hundreds of feet in the air. You might be covered with debris in the pool.

The other risk is the risk of electrocution. Lightning accompanies a tornado either before or after. Think of being electrocuted and thrown hundreds of feet into the air.

In addition to that, you come down, and you are covered with debris. It is never a good idea to be found in a swimming pool at this time. The good thing is that the national weather service alerts people when severe weather is likely and the most likely time of day as well.

There are high caliber instruments and satellite imagery. The residents are usually warned in advance before the tornado strikes. Swimming in a pool during a tornado would be your liability.

This is not always the case however, since a tornado can form and touchdown without warning. During weather aware days and seasons, always be alert of changing clouds and weather.


Hailstorms can also accompany thunderstorms and tornadoes. Hail is frozen water to form ice. The size of the solid ice varies. It might create a big hailstone. This hailstone can hit you whether you are in the pool or standing next to it.

During a storm, try to avoid open areas. A one-centimeter hail stone hits the ground at a speed of 9m/s. The size of the hailstone affects the rate, in addition to gravity. Even as you seek shelter in your house, stay away from windows and other structures made of glass.

Hailstones have been known to shatter glass windows and cause injuries. For added safety, you should put plastic tapes in your windows to minimize instances of shattering glass. Avoid seeking shelter beneath trees and tents during hailstones. Always stay indoors.

Bottom Line

You now get the general idea of why it is hazardous to swim during thunderstorms, tornadoes, and hailstorms. The amount of current in a bolt of lightning will even melt sand, and we haven’t talked about ear damage.

Whenever you hear lightning, scamper for safety. Whether in an outdoor or indoor pool, get out of the water. It is a good conductor of current, and you will die or develop severe defects from electrocution.

The strike distance is about a 10-mile radius. If you hear the rumble close enough, then it is in your area. It is advisable to use the flash to bang method or rely on data from national sources like TV broadcasts and private forecast entities.

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