Lightning Strike?

Having had several days of wicked heat, we had a fabulous storm last night, which passed pretty much overhead where we live. I know not everyone likes them, but I grew to love them many years ago when I lived in South Africa, and the weather was, at least from my young recollections, the same or hotter than here.

We switched off all the lights and went upstairs to watch. The trees were blown around and you could see some huge strikes of lightning not very far from us. Apparently, where we used to live in Mundelein was one of the hardest hit areas. Many people are without power as a result this morning. This Chicago Tribune report goes into more detail.

The reason for this post is more to learn about the storms though, as I find them fascinating, and I was chatting to a guy over lunch last week who shared some additional facts, so I thought I would go find out some more.

Basically, lightning is believed to be formed in Cumulonimbus clouds when strong air currents cause water and ice particles to bash into each other, causing electricity to build up. The positive and negative charges separate from each other, with the negative charges dropping to the lowest parts of the cloud, positive staying higher. Positive charges are also built up on the ground below.

When the charges become big enough then there is a lightning strike, as the positive charge on the ground meets the negative charge in the cloud, which looks like it shot from the cloud to the ground. This is in fact one of the biggest misconceptions. In fact the positive charges leap from the ground to meet downward streaming negative charges, and the light is created when they meet, which apparently makes it look like the strike came down, and all of that in 1 millionth of a second. It's amazing anyone ever gets it on film.

Thunder is created when the lightning, which is hotter than the sun at between 30,000-50,000 degrees Fahrenheit, heats up the air around it. The air expands so rapidly that it sends out a shock wave and therefore the crack happens. The closer you are to the storm, the more of a crack you will hear. As you move further away from the storm you will hear more of a rumble as the sound bounces around off hills, buildings, trees, etc.

I love this little quote from the Tampa Bay Disaster Website where you can also find some other interesting myths and facts. "(If you are outside and) you feel your skin tingle or your hair stand on end, squat low to the ground on the balls of your feet. Place your hands on your knees with your head between them (and kiss your ass goodbye). Make yourself the smallest target possible and minimize your contact with the ground." The only bit that is missing is the bit I added in red!

Isn't nature awesome!