What causes lightning? There is still a lot of research being done on lightning and some of the exact details of its creation. The most accepted research suggests that ice, hail, and semi-frozen water drops known as graupel are essential to lightning development. Storms that fail to produce large quantities of ice usually fail to produce lightning. We can think of it like when we drag our feet on the carpet on a dry day in winter and touch something or someone to get that shock.
Similarly in clouds, these ice crystals bang into one another, creating a frictional charge that builds up and separates in the cloud. Typically, these charges separate into a positive and negative within the cloud and begin to branch out into what are called stepped leaders as they feel the presence of each other. In other words, opposites attract. At the same time, there are also charges that build up and accumulate at the ground level. These ground level charges begin to reach upward via the stepped leaders through objects on the ground such as trees, poles, mountain tops and even humans. The taller the object, the closer it is to the cloud base where the bulk of the electrical charge resides. If the ground stepped leader intercepts the cloud stepped leader, a connection is made and the electricity flows from the cloud to the ground through the object on the ground.
Remember, lightning is electricity and electricity is looking for the shortest path to the ground. This is why we always advise you to seek shelter indoors during a thunderstorm and away from tall objects. If you are caught outside and cannot find shelter, go to a low-lying, open place away from trees, poles or metal objects. Then make yourself the smallest target possible – don’t lie flat on the ground, but squat low and place your hands on your knees with your head between them. And no…rubber-soled shoes do not offer protection from lightning.
Lightning Safety Week begins Sunday, so I encourage you to take the time to learn how to stay safe when thunderstorms threaten. In Georgia, lightning is the No. 3 weather-related killer. Nationwide, an average of 54 people are killed each year by lightning – and hundreds more are severely injured – so it’s important to protect yourself and your loved ones before the next potential strike. Find out more about how to prepare for lightning and other severe weather hazards by visiting www.ready.ga.gov, www.srh.noaa.gov/ffc/ or www.srh.noaa.gov/jetstream/.
Keith Stellman is the Meteorologist-in-Charge at the National Weather Service’s Peachtree City office