Thunderbolts and Lightning, Very Very Frightening Me!

Summer is here, the time of lazy days, high heat, fireflies, and of course, thunderstorms. Thunderstorms can happen anywhere at any time, but are most likely to happen when it gets hot. Here in the east where I live, my thunderstorms are most frequently in the late afternoon. In the Midwest, they usually happen in the evening or overnight. Where do these storms come from?

There are two ways for a thunderstorm to form that I’ve noticed. The first is associated with a cold front. Usually, what I’ve seen is we’ll be in a heat wave (three or more days of temperatures above 90̊) and when a cold front comes in to cool things off a bit, the contrast between very hot and less hot air causes enough atmospheric instability that severe thunderstorms form all along the front.

Afternoon thunderstorm building over Pennsylvania

The other situation, and this is my favorite, is what I call the pop-up storm. These happen later in the day and form when the heat and humidity of the day force hot air to rise. As the air rises it cools and condenses into clouds. If the cloud gets tall enough, the water vapor molecules eventually for ice crystals. If the ice crystals collide with each other, they can create an electrical charge. The electrical charge is lightning. A bolt of lightning is hotter than the surface of the sun and causes the air around it to superheat. The rumble of thunder you hear is the sound of superheated air expanding.

Anvil cloud from a dissipating thunderstorm

Lightning is lazy. When cloud-to-ground lightning strikes, it looks for the shortest and easiest path to the ground. That means the tallest object around. Being in a flat, open area (such as a beach, the rim of the Grand Canyon) or on a prominence such as a hill or mountain makes you a target. Avoid those areas. Also, stay away from tall objects like trees. Get out of the water when you hear thunder. A good rule of thumb is if you can hear thunder, the lightning is close enough to hit you. Pretty much anything indoors is a safe place to hide from lightning, as long as it’s not made completely out of metal.

Lightning strikes near Crater Lake

Another way for thunderstorms to kill you is with a flash flood. Don’t try to drive through water on a roadway. Listen for a rushing sound if you’re hiking in a canyon and move to higher ground. Even if it’s not raining where you are, a flood from rain upstream will find you so be aware of local weather conditions.

A pair of storms approaches in Wyoming

Hail sometimes accompanies a thunderstorm. While it can be cool to see everything covered in ice during the summer, large hailstones can cause property, crop, and people damage. An umbrella won’t protect you from a frozen baseball that’s been falling for thousands of feet so get inside. Also, hail is an indicator of possible tornadoes. Refer back to this post from March.

Odds are pretty good you’ll survive the next thunderstorm. Take the time to relax by listening to the sounds of the rain and thunder. Appreciate all the complexities and nuances that go into making nature’s rumbly light show.

This week's information comes via the National Severe Storms Laboratory All photos are my own.