Lightning (HB)

Lightning (HB)

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There is an abundance of facts, figures, and statistics about lightning and electricity in general that are interesting but not super helpful. We still need to have a basic understanding of how it works. You need to know how to mitigate and prevent the potential risks associated with lightning and electrical injuries. You also need to understand the best practices for treatment.

Think of an electric current like the current in a river. The steeper the gradient of the river, the faster the water will flow. The other factor is the amount of water that is in the river. More water is more force. Volts are like the gradient in the river–the higher the volts, the faster it flows. Amps are like the amount of water–the higher the amps, the more power it has.

Household electrical current is AC (Alternating Current). It flows in both directions at 60 cycles per second–much the same as the body’s electrical conduction system. Batteries and lightning are DC (Direct Current), meaning it only travels in one direction and is a “continuous flow” of electricity. When a human comes in contact with an electrical current, the damage done depends on both the time exposed and the amount of current passed through the body.

AC likes to follow nerve pathways and blood vessels, so most of the damage is caused internally. Because AC mimics our electrical system, it causes muscles to contract and relax rapidly. Since this happens 60 times per second, sometimes people can’t let go. If the patient grabbed a live wire with their hand, the muscles clamp down, and they can’t release it. In the United States, a residential electrical circuit might be 110 volts and 20 amps, but a person could be stuck on it for several seconds.

DC likes to get to the ground as quickly as possible, and it tends to run on the outside of the body. Lightning is exclusively direct current, and it generates around fifteen million volts at approximately 20,000 amps. But that current only lasts for around one ten-thousandth of a second.

Lightning is an electrical discharge that nature uses to equalize the static charge buildup between the ground and atmosphere. Most lightning occurs within the clouds and is harmless to us. Sometimes the lightning will reach the ground, and this is the form we worry about. Not only is the bolt of lightning itself dangerous, but it also creates streamers, a ground current, and a concussive blast.

Leader strokes seek downward from the atmosphere and are eventually met by a streamer that projects upwards. This can occur anywhere between 50 and 100 meters. The streamer can rise through anything–a building, a tree, or a person.

When the leader and streamer meet, a circuit is created, and electrical current flows between them. The massive negative charge continues toward the ground along the path of the streamer. Around 5% of cloud-to-ground lightning bolts exhibit a reversal of this pattern where a positive charge seeks the ground. The relevance here is that the bolts are much stronger and can travel significant distances–some have been recorded as touching the ground 10-15 miles from the point of origin, even crossing over mountains.

Injuries from lighting are a factor of how close the patient was to the source and what part of the lightning affected them. Nearly everyone nearby will have some deafness from the concussive displacement, so you will need to anticipate communication problems. Consider writing questions to patients.

Patients near the strike could have injuries from shrapnel like rocks (if the strike hit a rocky or gravelly area) and splinters (if a tree was struck).

Patients in the area of the ground splash, or otherwise somehow connected to a conductive surface like a barbwire fence, or in a field of wet grass, could experience a number of effects related to electrical injury, including cardiac issues, seizures, burns, etc.

You can treat cardiac arrest from lightning strikes very effectively with good CPR. If we can safely and quickly start CPR, there is a good chance to get the heart restarted. The heart will likely restart before breathing as the brain takes longer to reset.

If you can get inside someplace, an enclosed building is the safest place to shelter. A carport or a metal covered area is not the safest place. Inside of a vehicle is a good place to shelter. DO NOT shelter under a car.

Height and proximity to other objects are two key factors in predicting where lightning strikes. If a lightning strike is imminent, seek shelter if you can. If caught in the open or outside, separate from other people, insulate yourself from the ground by getting on a pack or foam mat, get as low as possible, and keep anything touching the ground as close as possible.

Myths and facts:

  • Metal objects attract lightning strikes.
  • Lighting is attracted to the tallest object in the area, with the largest difference between positive and negative charges but not if they are good conductors. This is not
  • referring to a javelin or metal flag pole or something.
  • If you have a radio, you do not need to turn it off–radios do not attract lightning.

References