When Lightning Strikes

By wildgirl -

 As we go through the peak of the hurricane season, Dr Anjani Ganase warns of the perils of lightning strikes. Watch from a safe place and wonder at nature’s amazing light shows.

 

There are many forms of lightning strikes. Within storm clouds, positive and negative charges form as ice particles move around under turbulent conditions. Typically, the top portion of the cloud develops a net positive charge, while the bottom of the cloud becomes net negative. Sheet lightning is the result of the discharge of these charges and the formation of electricity within the clouds. Sometimes the discharge occurs between the cloud and the earth and there are four different lightning patterns that can be formed staccato, forked, ribbon and bead lightning. A negative lightning strike occurs between the net negative charge of the cloud base and the earth where it grounds itself. Conversely, positive lightning strikes are rarer where the positive charge of the cloud found at much higher altitudes is able to break through the negative portions of the cloud and discharges with the ground. When the strike originates from such great heights, the discharge is more powerful and much more dangerous. 

 

 
 Lighting over Boston 1967, Photo courtesy The Boston Globe, NOAA Photo Library

 

The thunder heard when lightning strikes is the sudden expansion of the air around the strike of the lightning. As the speed of sound is slower than light, you can measure the distance between yourself and the lightning strike by counting the seconds between the lightning seen and the thunder heard.  Every five seconds is equivalent to one mile.

 

Lightning can get hotter than the sun and it travels at the speed of light.

 

When there is a thunderstorm, if your house is struck by lightning, the electricity will cause a power surge as the electricity finds the fastest pathway to the ground either through your electrics or your pipes. Many homes are built with lightning rods to redirect the electricity and avoid excess damage to the house, however, there still may be some risk of fires.  Avoid using electronic appliances and running water unnecessarily in your home during a storm. When a person is struck by lightning, they’re not charged so you can be in contact and offer help.

 

Rubber does not insulate you from a lightning strike. Even though rubber is an electrical insulator, the thin soles of your shoes will not be enough to protect you. Neither will rubber tyres help to protect you in your car. Actually, the metal shell of the car can redirect the lightning as the electricity will move along the path of least resistance towards the ground.

 

Lightning may assist in evolution! Scientists suspect that lightning can cause the bacteria in soil to pick up DNA from their surroundings, as the electrical currents produced by lightning make their cell membranes more permeable.

 

Lightning can help plants grow with the process of nitrogen fixation. In the soils there are microbes that can naturally convert nitrogen gas into nitrites and nitrates by combining it with oxygen, which then gets absorbs by plants for growth. Lightning is also known to also cause the oxidation of nitrogen gas under tremendous heat which then ends up in the soil during rainfall.

 

Church bells were rung continuously during thunderstorm storms to ward off the lightning. Unfortunately, this practice led to the death of many bell ringers while they rang the large metal bells in high towers. Maybe the bell towers did prevent the lightning from striking other places in towns as they acted as lightning rods.

 

Lightning can strike a place twice even three times or more. In fact, there are places that are more prone to lightning strikes. The most struck place on earth is Maracaibo Lake in Venezuela (with an average of 28 strikes recorded in one minute!)

 

Helicopters can cause lightning strikes, particularly in the North Sea where helicopters were being struck during the winter months due to the large build up in a negative static charge. This became part of forecasting. In high risk areas when the air temperature is close to zero degrees Celsius with a high chance of precipitation, people are alerted to the potential hits to the rotor or tail of their helicopters.

 

Apart from storms, there are other things that cause lightning such as a volcanic eruption. Emitted volcanic plume and ash can cause volcanic lightning from the built-up static charges during an eruption.

 

Lightning can produce amazing glass shapes – natural sculptures called fulgurites - when it strikes sand. The hollow tube produced by the lightning is surrounded by petrified sand, clay and soil in unusual shapes.

 

As we are in the height of the rainy season, please be mindful of lightning. Seek shelter in a house, do not hide out under a tree or even lie on the ground.

 


 

References:

https://www.newscientist.com/article/dn1102-lightning-provides-vital-spark-for-evolution/

 

https://www.metoffice.gov.uk/weather/learn-about/weather/types-of-weather/thunder-and-lightning/facts-about-lightning

 

https://www.skybrary.aero/index.php/Helicopter-triggered_Lightning_Strikes

 

https://www.theguardian.com/news/2011/jun/16/weatherwatch-lightning-thunderstorm

 

https://www.weather.gov/safety/lightning-myths

 

https://en.wikipedia.org/wiki/Volcanic_lightning

 

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