Lightning

a lighting is an atmospheric electrical  discharge accompanied by thunder, usually associated and produced by cumulonimbus clouds, but also during volcanic eruptions or in dust storms.A lightning can travel at speed of  220,000 km/h and can have a temperature of about 30,000 ºC. There are more than 16 million lightning storms in the world every year.Lightning causes ionisation in the air through which it travels, leading to the formation of nitric oxide and ultimately, nitric acid, of benefit to plant life below.

Lightning can also occur within the ash clouds from volcanic eruptions or can be caused by violent forest fires which generate sufficient dust to create a static charge.

How lightning initially forms is still a matter of debate. Scientists have studied root causes ranging from atmospheric perturbations (wind, humidity, friction, and atmospheric preassure) to the impact of solar wind and accumulation of charged solar particles.Ice inside a cloud is thought to be a key element in lightning development, and may cause a forcible separation of positive and negative charges within the cloud, thus assisting in the formation of lightning.