What is a lightning storm?
A lightning storm is a weather phenomenon caused by a cumulonimbus cloud. It is accompanied by thunder and lightning and sometimes by strong winds and precipitation, as well (according to the United States National Oceanic and Atmospheric Administration, NOAA). In simpler terms, it’s the appearance of electricity in the atmosphere.
Lightning storms are generated by heat and humidity, so they can occur anywhere in the world as long as these conditions are guaranteed. It is essentially a product of the combination of hot air rising from the Earth’s surface and a force that allows it to lift, such as a sea breeze, a mountain, or a cold front.
About two thousand lightning storms are happening around the world at any given time.
How does a lightning storm start?
A lightning storm requires the presence of humidity, rising air, and a lifting mechanism that pushes the air. With these three elements in consideration, the atmospheric phenomenon occurs when hot air from the lower layers of the surface rises, allowing surface water to evaporate and raise the moisture in order to form clouds.
These clouds accumulate, grow, and darken as they fill with water. Meanwhile, cold, dry air from the upper layers of the atmosphere, or downdrafts, carries moisture downward and causes it to fall as rain.
The clouds that form and cause lightning storms can reach up to 16 km high. Lightning can reach temperatures of up to 30,000º Celsius, which causes the white light of the electrical discharge. On the other hand, the sound of thunder is a result of the hot air that expands, generating a shock wave.
What are the phases of a lightning storm?
Every lightning storm has a life cycle of three phases or stages:
1. Development: also called the cluster phase, this is when the mass of moisture rises into the atmosphere and the clouds begin to get larger. If the mass consists of water and no lightning is generated, it will not be called a lightning storm. At this stage, particles of ice crystals start to be produced at the top of the cloud.
2. Maturity: the cloud is a cluster growing upwards; when it has reached its maximum vertical development, the cumulonimbus is formed; its interior consists of descending air currents in the form of precipitation that falls intensely in the lower part of the atmosphere. Inside the clouds, a phenomenon of turbulence arises, and flashes of lightning appear across the entire expanse of the clouds.
3. Dissipation: in this stage, the clouds disperse to the sides, and the warm air from the surface is replaced by cold air. At this stage, there are only downdrafts, and the precipitation gets weaker and weaker.
What types of lightning storms are there?
The main types of lightning storms are:
1. Single-cell storms: they are the weakest storms and are isolated and brief; they do not feed back on energy.
2. Multi-cell storms: they have two or more cells. They are more intense and longer than single-cell storms, in addition to being accompanied by wind or hail. This is one of the most common types and includes a series of lightning storms.
3. Supercell storms: these are the most intense and are capable of producing tornadoes. These storms feed back on themselves, thus maintaining their charge of electrical energy.
4. Squall line: this is a line of active storms hundreds of kilometers long. They are usually accompanied by gusts of hurricane-force winds and heavy rains.