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Will Water Protect You From An Explosion?

The answer to this question may seem obvious, but it isn’t what you think. The dangers of an explosion include, but aren’t limited to, shrapnel, fireballs, and pressure waves. I have always thought jumping into water would protect me from the brunt of an explosion instead of facing it on land. But will water protect you from an explosion?

Enduring an explosion in water is far more dangerous than facing an identical explosion on land. Water is incompressible and thus will not absorb the pressure from an explosion but move with it. The increased pressure being transmitted has a high chance of killing you if not causing severe injuries.

There are several dangerous factors to an explosion, from the fireball to pressure waves and shrapnel; being in the blast vicinity makes it near impossible to escape unscathed. Being in air or water during an explosion holds different primary risks and dangers. Though you may escape one aspect of the explosion, you are open to other threats.

Will Water Protect You From An Explosion?

The threats an explosion poses differ significantly depending on whether it is on land or in water due to how the different atmospheric densities, among other qualities that react with an explosion’s characteristics.

An explosion on land commonly burns skin, tears limbs apart and propels shrapnel and other objects through the air. An explosion in water is likely to have a deeper-set effect on your body, compressing the gases in air chambers in your body and likely killing you.

However, being underwater during an underwater explosion is very different from escaping an explosion on land.

What Happens In An Explosion?

Explosives are essentially just elements that burn or decompose at an incredible speed. The chemical (or nuclear) reaction breaks down compounds into highly compressed gases and produces heat from the exothermic reaction of molecules being blasted apart. The gases rapidly expand with the heat speeding up the gas particles, further increasing the overall expansion speed.

This fast-expanding gas – called a pressure wave – is the key to an explosive’s destructive power. If the pressure wave is fast enough, specifically if it breaks the sound barrier, it will have the power to generate a powerful shock wave.

The injuries caused by explosions are categorized as the following:

  • Primary Blast Injury – The direct effect of changes in atmospheric pressure caused by the blast wave rarely occurs without evidence of secondary, tertiary, or quaternary injuries.
  • Secondary Blast Injury – When objects propelled by the energy of the explosion hit the victim, causing blunt or penetrating ballistic trauma.
  • Tertiary Blast Injury – When a victims’ body is displaced by expanding gases and high winds, trauma occurs from tumbling and impacting objects.
  • Quaternary Blast Injury – This covers injuries from all other causes: inhalation of dust, smoke, carbon monoxide, and other chemicals, burn from gasses or secondary fires, and crushing injuries from structural collapses.

An Explosion On Land

In an explosion surrounded by air, one of the main dangers is the shrapnel and other objects propelled from the force of the explosion. The atmosphere will compress and absorb some of the explosive energy caused by the pressure and shock waves – decreasing the explosion’s lethal radius.

Skin is comprised of molecules that are closer together than those of the gas molecules in an explosion. Due to the different densities, when a pressure wave travels through the air and connects with an organism, the body will reflect most of the force. However, parts of the body contain gas, meaning they have the same density as the gas in the pressure wave. While most of the pressure wave is reflected, some of it compresses these internal gases, causing primary blast injuries.

Primal blast injuries implode and rupture gassy chambers in the body, such as the lungs, ears, and sometimes the intestines, fragmenting the tissue.

An Explosion In Water

Water is seen as protective against an explosion due to the drag water exerts on objects and shrapnel propelled by a blast. The lessened impact of shrapnel compared to its detrimental impacts in air creates an illusion that water is safe. While water does protect you from a particular aspect of an explosion, it amplifies the dangers of others.

Water is dubbed incompressible due to the massive pressure it takes to apply a small amount of compression. This quality results in water’s lack of ability to absorb pressure waves, as water will not only move with the pressure but transmit it with greater intensity over a larger distance. When the wave hits the victim, it will pass through them, most of the power being reflected by the density of your skin.

However, the wave would hit the air pockets in your body, compressing the gases. This could result in blocked blood vessels, ruptured lungs, torn intestinal tissues, and brain hemorrhaging. The initial shock wave is followed by secondary repeat waves called bubble pulses. Further, if an underwater explosion occurs in a contained area, the waves will hit the sides of its containment and bounce back, worsening and inflicting more damage. 

Taking Cover From A Land Explosion In Water

Water’s ability to protect you from a bomb on land completely depends on the type of explosion and the distance between the explosion and the body of water.

A fireball following an explosion is where the air absorbs most of the immediate harmful gamma and soft X-rays, causing it to heat up and create a massive shock wave. Water can lessen the immediate danger of the fireball; however, depending on the size of the body of water, the radiant heat will boil the surface of the water without heating the rest of the body. Due to the speed of gamma rays, you would have to be very deep underwater to escape any amount of damage.

Even though the explosion is on land, the same physics of blast waves carrying through water apply. While these pressure waves are not as intense than if the explosion originated underwater, if the explosion is close to the water, the pressure waves which reach it will still carry through the water, causing more damage than they would have in air.

How To Protect Yourself From An Explosion

Overall, it is likely safer to stay on land during an explosion and practice protective methods there instead of hiding underwater. The following shows how to try to stay safe from an explosion:

  • Shelter – To protect yourself from any possible radiation, it is best to find a strong structure for shelter. Stay away from windows, doors and exterior walls. Being underground is ideal.
  • Take Cover – If you cannot get into proper shelter, take cover behind anything that may be able to offer protection from the blast.
  • Lie Face Down – This will help protect your exposed skin from heat and flying debris.
  • Radiation – If the explosion was nuclear or high in radiation, you must get inside as soon as possible. Avoid touching your face, take off the contaminated clothing quickly, and shower or wash thoroughly. Stay away from and clean anything exposed to the fallout.

Conclusion

Water may protect you from the immediate threat of a fireball or shrapnel, but ultimately being underwater during an explosion can cause more harm than good. The pressure waves emitted by an explosion are the most prevalent threat to you during an underwater explosion, and unfortunately, there is no way to escape them.

Sources

Frank Pearmain

As a homesteader, survivalist, and previously a safari guide in Africa, I have extensive bush and wilderness experience. I am passionate about living a self-sufficient, off-grid lifestyle and continuously learn and strive toward that goal!

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