How does Lightning Occur?

Lightning occurs within a thunderstorm when supercooled liquid water (water that is still liquid at or below freezing temperatures) and ice are mixing with each other in below freezing temperatures. The reason this occurs in thunderstorms is that the updraft of a thunderstorm is forcing liquid water to rise up and mix with the ice in the colder (below freezing) layers of the atmosphere. The process by which charging occurs in thunderstorms is called non-inductive charging. Lightning eventually occurs as the charging is separated within a thunderstorm with the supercooled liquid water retaining most of the negative charge and the ice retaining most of the positive charge. The two main types of lightning are intra-cloud and cloud-to-ground. Intra-cloud or IC lightning occurs when there is lightning between the negatively charged region of the cloud and the positively charged region of the cloud. Cloud-to-ground or CG lightning occurs when there is lightning between the negatively charged region of the cloud and the ground.

In strong to severe thunderstorms with very strong updrafts, the charging structure of the thunderstorm becomes more complicated. It’s not just as simple as there is a negatively charged region and a positively charged region. This becomes even more complex when you have clusters of thunderstorms, some of which are decaying and some of which are maturing all in the same area. This is what makes lightning so difficult to predict and so dangerous for people outside. While lightning deaths in the United States are on the decline, it is still one of the biggest killers of all weather phenomena.