What is Lightning?

Lightning can be bright, fascinating, but most importantly dangerous. Over a whopping 100 million lightning strikes occur within the U.S. each year.

What is lightning?

Lightning is a blazing hot surge of electricity that forms during thunderstorms. There are various forms of lightning.

What forms of lightning are there?

• Cloud-to-Ground: Lightning stretches from the cloud all the way to Earth’s surface. This type of lightning is the “bolt” that strikes homes, cars and trees.
• Cloud-to-Cloud: Lightning that jumps between at least two different clouds.
• Intra-Cloud: The lightning that usually is just a flash in the sky. This lightning occurs within a singular cloud.
• “Bolt From the Blue”: A special type of lightning that occurs when lightning from a thunderstorm extends all the way to an area that is not experiencing a thunderstorm at all and may have blue skies above. “Thunder roars, head indoors” is so important. Lightning can occur miles from a thunderstorm and can often catch people by surprise, putting them in danger. This is why pools, sporting events and other outdoor activities often enforce 30-minute since last lightning policies. The policies ensure it’s safe to be outdoors well after the thunderstorm has passed.
• Heat Lightning: There is no such thing! Often during summer nights, flashes of lightning can be seen high in the sky, but thunder may not occur and a storm may never come. Heat lightning is just distant lightning seen on the horizon from an actual thunderstorm. This lightning can be from storms that are 200 miles away!

How does lightning form within thunderstorms?

Thunderstorms themselves are very complex and interesting forms of weather. A thunderstorm needs warm air at the surface and cold air higher up to begin to develop. When these ingredients are in place, convection, or the rapid rise of warm air, occurs. Convection then forms clouds that have both liquid water droplets and frozen ice crystals, as the air high above the ground can be very cold. Water droplets and ice will interact, bumping into each other quickly. The rapid movement can cause different charges to develop. Air acts as an insulator. Once the negative charge in the cloud becomes large enough, it will connect to the positive charge elsewhere, forming an electric current that breaks through the insulator. This current is seen as lightning.

Why is lightning so dangerous?

Lightning is extremely dangerous and that’s partly due to its temperature. A bolt of lightning can be as hot as 54,000 degrees F! This is almost 6 times hotter than the sun. Besides the heat, lightning contains another obvious danger, it’s electricity. Up to 100 million volts of electricity can be contained in lightning, compared to high-voltage power lines that carry a mere 345,000 volts in comparison. There are many potential side effects when being struck from lightning, including:

• Vision loss
• Hearing loss
• Cardiac arrest
• Chronic pain
• Severe burns
• Death

When is lightning most dangerous?

The time lightning is most dangerous is not during the storm, but actually just before and after. Yes, lightning occurs while a thunderstorm approaches, is overhead and exits. However, people’s actions determine when lightning is most dangerous. Just before and after the storm, the sun may be out, which some people see as a sign to stay outdoors. However, lightning can still occur, strike and be deadly. During the thunderstorm itself, people are usually indoors so the risk of being struck is much lower. Lightning indicates other severe weather hazards. A strengthening storm usually can be indicated with its amount of lightning. Other severe weather hazards such as tornadoes, hail and damaging winds are reported with lightning. Ninety percent of severe weather reports have lightning occurring at the same time!

Interesting lightning facts:

• An average of 27 people die of lightning per year in the U.S.
• Over 200 injuries per year due to lightning in U.S.
• In 2019, Texas received the most lightning strikes in the U.S. with over 16 million strikes

Sources: Earth Networks, National Weather Service, UCAR
Story Image: Credit: NOAA