Lightning put simply, is a bright flash of electricity, caused during a thunderstorm. Lightning can also be observed during volcanic eruptions, surface nuclear explosions and forest fires. It travels up to a speed of 60,000 meters per second and has the power to kill more people each year than a hurricane or a tornado.
What Causes Lightning?
After convection when the warm, evaporated water rises into the atmosphere, it is encountered by cold air, which causes the warm air to rise even more rapidly and form large, dense and tall cumulonimbus clouds (thunder clouds).
Water from the lakes, rivers, ponds, oceans and all other water bodies on the surface of the Earth evaporates and rises into the Earth's atmosphere in the form of gas by a process called convection.
Further, the positive and negative charges separate from one another, wherein the negative charges move towards the bottom of the cloud and the positive charges dwell in the upper and middle regions of the cloud. The negative charges cause positive charges to develop in the area surrounding the cloud and on the ground below.
For better understanding, scientists have classified the different types of lightning based on their physical and visual characteristics.
Lightning bolts have temperatures ranging from 30,000 to 50,000° F, which is extremely hot, even hotter than the surface of the Sun. Once the air, the Earth and the cloud have been neutralized by the lightning, it will not strike again. However, at times more than one strike is required for neutralization and this is known as a lightning storm.
In the case of lightning during thunderstorms, lightning is produced as a result of collision between water particles, however, in case of lightning during volcanic eruptions, collisions between ash and dust particles result in lightning.
Separation of positively and negatively charged particles occurs in the volcanic cloud, which causes the cloud to be positively charged at one particular end and negatively charged at the other end.
This charge separation goes on increasing until a point when it is beyond resistance and electricity begins to flow between the opposite charges. Thus, lightning display occurs during an eruption.