Cloud-to-ground lightning and your daily forecast

Posted: Updated:

PHOENIX – Arizona has a lot of lightning. Each year, several hundred thousand cloud-to-ground lightning strokes are recorded, mostly during the summer thunderstorm season. 

One of the questions we get very frequently is; Does lightning strike up or down?  The interesting answer is “it depends how you look at it.”

With an emphasis on “look,” the first flash of lightning we see is actually traveling from the ground to the cloud.

However, in the milliseconds before the flash, a path of negative electricity that we can’t see is actually making its way toward the ground. So scientifically speaking, it is “cloud-to-ground” lightning.

Here’s the explanation from the National Severe Storms Laboratory:

Cloud-to-ground lightning comes from the sky down, but the part you see comes from the ground up. A typical cloud-to-ground flash lowers a path of negative electricity (that we cannot see) towards the ground in a series of steps. Objects on the ground generally have a positive charge. Since opposites attract, an upward streamer is sent out from the object about to be struck. When the two paths meet, a return stroke zips back up to the sky. It is the return stroke that produces the visible flash, but it all happens so fast (in about one-millionth of a second) so the human eye doesn't see the actual formation of the stroke.

For more information on lightning, check out: http://www.nssl.noaa.gov/primer/lightning/ltg_basics.html.

For cool pictures of lightning check this out. Susan Strom lives in Arizona:
http://www.lightninglady.com.