A "Thunder-full" Escape; effects of a thunderstorm

Some days ago, a friend was narrating his ordeal of how he narrowly escaped being killed by a thunderstorm. I was skeptical and said "really? You can't be struck by lightning and live to tell the tale." So he told me everything that happened, and it turns out he wasn't directly struck by a lightning but he was a victim of the indirect effect of a lightning storm. I'm pretty sure most of us have seen a thunderstorm at some point in our lives but do you know how powerful they can be? because I didn't, so I got to digging and together we shall explore the knowledge of "thunderland." Ready player one? Start!
Source: Pixabay

Thunderstorm is a natural phenomenon that happens in the cloud and it usually result in heavy rainfall and strong wind movement. It is usually identified by the presence of lightning. A thunderstorm can also occur without rainfall or any other form of precipitation and are referred to as "dry thunderstorm."

There is a "school of thought" that thinks heavy rainfall is the underlying cause of a thunderstorm, True or False? We shall find out together

Formation of thunderstorm

For a thunderstorm to occur, these 3 conditions must be met: moisture, air instability and heat.

When these three conditions are present, they interact together to bring about the formation process which undergo three stages;

Cumulus stage:
This is also known as the developmental stage.

Here, atmospheric air also known as air parcels begin to move upward, this upward movement is possible because of the heat from sun which relatively increases the temperature of the ground and indirectly temperature of air on ground level increases also which prompts the air to rise above the surrounding cool air (warm air has a lower density than cool air). As the air parcels keep rising, they get to a height where the air parcels begin to condense to liquid drops of water which quickly freezes (because of the relatively low temperature at high altitudes). These condensed liquid drops of water are what appear to be the cumulus cloud. The upward displacement of air parcels through convection into the sky to form cumulus cloud is called an updraft. The formation of cumulus ends the development stage and initiates the second stage.

The mature stage:

As the warm air continues to move upward it reaches an area in the sky where it can go no further instead it begins to spread outward within the cloud. This hindrance is caused by the tropopause. Now the cloud is very high and cold and is mostly dominated by updrafts with a flattened anvil shape. Cloud of this type and shape is called cumulonimbus. At this stage, precipitation reaches the ground (usually rainfall) and as the rain is falling it drags surrounding air down along with it creating downdrafts. The "hallmark" of this stage is basically the presence of both updrafts and downdrafts. This stage is where the storm is at its highest intensity, the updrafts travel at their highest speed, rainfall is at its highest, lightning is very frequent and wind is gaining speed.

The dissipating stage:

Here, the storm wears offs relatively fast and the downdraft is much more dominant over the updraft as the rain keeps falling but not heavily anymore because the supply of air to the updraft is now inevitably cut-off by the rain-induced downdraft which touches the ground and spread out in a process called downburst to form what meteorologists call cold pool. After the downburst, a barrier between the rain-cooled air and the surrounding air mass is created and is called the outflow boundary. Since the downdraft has literally cut-off the air supply to the cumulonimbus cloud which inevitably disappears.

Categories of thunderstorm

Single Cell Storm:

These are thunderstorms that are rarely severe and majorly occur due to instability in atmospheric air. Though they may not be severe, strong wind and heavy rainfall should be expected (as these are basic characteristics of any thunderstorm). Single cell storm have only one route of updraft and are often formed in regions of warm moist air.
All three stages (birth, life and decay) of the thunderstorm all happen within the span of 30 minutes for a single cell storm.

Multi Cell Storm:

These are just a "bunch" or "group" of single cell storms that form and move together at various stages in their life cycles. They can last for many hours even though each cell within the multi cell only last for about 30 - 50 minutes. So how can multiple single cell storms coexist as a gigantic piece? They do this all thanks to the outflow boundary. If you can recall, the outflow boundary is the barrier that separates the downdrafted cool air from the warm atmospheric moist air. In multi cells, there is always a mother cell with a restricted outflow boundary which initiates new storms. This requires strong wind to blow towards the level of the outflow boundary which is relative to the movement of the storm. This creates another upstream of warm moist air that forms another cumulus cloud which eventually develops into cumulonimbus cloud and the chain reaction goes on and on. Multicell storms rarely lose access to warm moist air to initiate a new storm within an pre-existing storm. This self-perpetuating process could go on for hours making them severe compared to single cell storm. But in comparison to the supercell storm, it's child's play.

Super Cell Storm:

If you think the multicell is "badass" wait till you learn about the supercell. Supercells are very dangerous and destructive both to lives and property, they are accompanied by large hails and extremely strong winds. The major factor in the formation of a supercell (assuming obviously, that there is constant supply of moist air to the updraft) is strong vertical wind shear. The wind shear causes the strong updraft (most can travel at a whooping speed of 150 mph) to carry the air around it and rotate it around a vertical axis causing a mesoclyne. The mesoclyne is the major characteristic of a supercell and is famously known for its extremity - as some can spawn strong and violent tornadoes. Supercells also spark the most frequent lightning with rates often exceeding 150 flashes per minute.

What's a thunderstorm without lightning?

Flickr Author: Ronan

During a thunderstorm electrostatic discharge happens and are referred to as lightning. The phenomenon behind the process of charges that create lightning is not properly understood by scientist but there has been significant advances made. For electrostatic discharge to occur, there must be two opposite charged bodies. With this in mind, lightning can strike from Cloud (+) to Ground (-), Cloud (+) to Cloud (-) or within the same cloud (Intra-Cloud lightning).

During the development of a thunderstorm, electrical charges are forced to be separated.

Positive charges are carried from the ground to the storm cloud (cumulonimbus) via updraft of air parcels and similarly negative charges are driven downwards via the downdraft by rainfall to the mid or lower level of the storm. The negative charges at the lower level of the storm attracts the positive charges on the ground directly below the storm since opposite charges attract. This continues to happen like clock-work and the connection between the two opposing charges grows stronger and stronger until they can grow no longer and the charges must be discharged. This prompts a finger of negative electricity (not visible to the eyes) to shoot downwards in an attempt to connect with the positive ground charges - in most cases, it misses at the first trial and this continues until the positive charges on the ground decide to meet it halfway and unite. It is at this junction it becomes visible to us in the form of a lightning strike.

Hit me for more detailed explanation of the process as the one above is more like a summarised version of the Cloud to Ground lightning.

Lightning produces radiations ?

In 1925, It was theoretically predicted that lightning bolts can produce X-rays^[1] but there was no proof whatsoever until 2001/2002 when a group of researchers at the New Mexico Institute of Mining and Technology discovered X-ray emissions after lightning stuck the ground trail left by a rocket and is published in their article by Dwyer, J.R et al. The electromagnetic radiations emitted by thunderstorms are relatively harmless.

How does thunderstorm affect us and our environment

As we should all know by now, thunderstorm comes with a lot of "associates" which include lightning, high wind speed (some clocking 50mph), hails and in extreme cases tornadoes. All these have direct and indirect effect on us and our environment.

Of them all, the effect of lightning is the very common but not as profound as the casualties that comes with tornadoes.

Lightning can affect us directly if all of the lightning's energy is directed through the human body or through the skin. In most cases, lightning of this kind can prove to be fatal or cause permanent injuries since an average lightning bolt carries 100 million to 1 billion volts according to NOAA. It is a very rare occurrence for lightning to directly hit a human as the data by NOAA claims that the odds of a man in his lifetime being struck by lightning is 1 in 13,000 (now that's a huge gap, isn't it). A person could still get hit by having contact with an object (usually a conductor) that has been electrified by lightning.

Indirect lightning can occur when lightning strikes an object or the ground and the current travels through the ground until it encounters another object to delegate it's current to. Indirect hit also has enough power to kill as well. Indirect hit is the more prominent and could be easily encountered. In 2016, BBC reported a lightning that struck the ground killing 300 deers at once.

Lightning also affects vegetation, as trees are good media for the conduction of lightning charges to the ground. Most trees are very tall (depending on its species) and we are quite familiar with the fact that lightning usually strikes the highest point making trees very successful candidates. A lightning strike is known to blast a tree trunk and in sparsely populated area, it could lead to the eruption of wild fire.

Precautions: better be safe than be sorry

_{Source: Wikicommons}

You may not know, but lightning alone which is one of the secondary effects of a thunderstorm has claimed many lives. Just in the United States, there has been an average of 33 annual fatalities just by lightning strike between 2004 and 2013 according to CDC, which puts it in second place for weather related fatalities behind floods. These stats alone should give us enough concern to learn about safety measures to take if we encounter an extremely severe storm or any thunderstorm for that matter.

safety 1: Ensure to stay indoors and away from all glass windows because of high velocity wind (that could shatter glass) and if you must be outside, do not stay directly under the stormy cumulonimbus cloud - as there is a high probability of Cloud-to-Ground lightning (it is better to stay in a vehicle and not touch any metal)

safety 2: Ensure you keep your feet insulated (flip flops are good for this) at all times during storm so as to prevent indirect conduction of a lightning charge from the ground to the body - especially concrete floors.

safety 3: Refrain from using any electrical appliance, phone and any plumbing equipment (like shower) as these all are great conductors of lightning charges from the ground.

There are many more safety guidelines by (like installing an earthing device) and can be read here.

Conclusion

Thunderstorm has earned a spot among the world's leading catastrophic phenomena and has a long lasting effect that cause permanent damage to the body or worse (death) yet many people still take their lives for granted during thunderstorms - like my friend. If only people lay much emphasis on ways to protect themselves from such occurrence, then we might be able to reduce the number of fatal incidents drastically. Wake up people! Ignorance is not bliss anymore.

_{This article is for educational purpose only and I hope one day the information conveyed here helps save a life.}

Thank you for time. One love!

_{All images are public domain and CCO licensed with embedded links}

References

1. Introductory meteorlogy
2. Storm and Cloud Dynamics by William R. Cotton et al. Academic press, 2010.
3. National Weather Service (2009-09-1). "Types of thunderstorm" National Weather Service Southern Region Headquarters.
4. Geoscience Australia (2007-09-04). "Where does severe weather occur?" Commonwealth of Australia.
5. American Red Cross "Thunderstorm safety checklists" by American Red Cross.
6. Federal Emergency Management Agency "Thunderstorms and Lightning" US Department of Homeland Security.
7. The processes that form Lightning.
8. Thunderstorms and Lightning
9. Thunderstorm on wikipedia