Lightning bolt 2

Lightning. It's not a welcomed sight and brings death and destruction wherever it strikes. It comes in second place behind floods with our dangerous weather.

But how does this fiery electricity form in the sky? Lightning strikes the Earth 44 times every second.

Lightning graphic

We see its flash and hear about its destruction of life and property on the news. But what do we really know about that electricity from the sky? How does it go from charges of electricity in the atmosphere to one of Mother Nature's most deadly weather phenomena that kills on average 51 people per year? 

Here's the set-up for lightning to occur.  In a storm there are negative charges. On the ground there are positive charges.

Electrons begin zigzagging downward. That’s known as a step leader. As the leader nears the ground it draws a positive charge upward.

As the leader and streamer merge apowerful electrical current flows. The return stroke is what we see, traveling at 60,000 miles per second. The process may repeat several times along the same path, causing a flicker.

Lightning bolt

The different kinds of lightning we can see coming from a thunderstorm include the most common, which is cloud to ground. According to the severe storms laboratory, there are five to 10 times as many cloud to cloud as there are cloud to ground lightning strikes.   

Then there's the kind we can usually only see at night, sometimes during the day too, but it is very common and it's called intracloud.

Next is cloud to sky lightning. This one is more rare and can only be seen on occasion. 

Cloud to cloud lightning is uncommon but does happen from time to time. And it's just that -- lightning between two clouds. It happens when two clouds have opposite charges. 

Another is cloud to ground, which is positive. They are usually associated with supercell thunderstorms and are known for not branching out. It's just a very distinctive lightning bolt coming down to the ground. This kind of lightning stands out because it's more intense and very bright compared to other forms of lightning.

lightning graphic

The rarest form of lightning is ground to cloud. As mentioned earlier, clouds have negative charges and the ground has a positive charge. And since opposite charges attract, an upward streamer is sent out from the ground or object about to be struck. 

When the two paths meet, there's a return stroke that streaks back up into the sky and that's what we see that produces the bright flash. However, it happens too fast for our eyes to pick up on it coming from the ground. It all happens in about one millionth of a second.


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