Why do some lightning storms make the ground glow?

[joel ewing]

I've seen this phenomena only 3 times in my lifetime. Last night Tucson had an incredible lightning show, which is typical during our "monsoon" season. However, there were several episodes of the surface atmosphere glowing an incredible blue-green prior and during CG strikes. Sometimes the ground and surrounding atmosphere lit up in these colors without any visible strikes near them. The manner in which the colors manifested was similar looking to the northern lights...however much closer to the surface. Please....can anybody answer this??? All of Tucson is in a buzz about it....and they're all looking to me for an answer. Help!

 

[Brandon Clement]

There was a show on either discovery, TLC or national geographic called mega lightning. The lightning it was talking about looked a lot like the nothern lights and was incredible. According to the show it is pretty rare and is just now starting to be researched, but the lightning was not bolts but looked more like a mushroom cloud. The strikes happened fast and were above the thunderstorm. I'm not to sure how they would look from under the storm. I tried to google mega lightning but could not find it. Maybe someone that knows more about this could elaborate since I am not a met and don't know a lot about lightning.

 

[Dan Robinson]

These are usually arcing or 'faulting' (short circuiting) power lines - they can either be caused by high winds damaging the lines, or a direct lightning strike that causes a 'flashover' across insulators.

Power line faults can be on the order of tens of thousands of amperes or more, therefore very intense and visible for great distances. Color is usually blue, green or a combination of the two. Sometimes orange can appear due to flames if the arc ignites wood on poles or oil in transformers.

http://wvlightning.com/powerflash.shtml

PTI, a New York power company, used to have an excellent web site demonstrating how this happens. They had automatic cameras set up all along their lines that were triggered by lightning and caught these flashovers happening at close range.

 

[Patrick Ware]

I see this happen all the time on my aircraft when I am flying through rain and charged clouds. It basically St. Elmo's fire. The ionization and charging of the atmosphere make it look like it is glowing. If I encounter this in the aircraft it is particularly affected by an increase in airspeed, freezing level, water particles and turning on the radar. If I wait too late to turn on the radar, a static discharge results along with a very loud "PoP".
I have also seen 8" electrical balls of St. Elmo's fire form in the cockpit and travel through the cockpit door and down the aisle accompanied with quite a bit of screaming from the passengers in the back as it move toward the rear of the aircraft and out. It's totally harmless but will definitely make you sit up and take notice. It's really very cool once you get over the initial shock (no pun intended) of it.

http://www.physics.northwestern.edu/classe...telmosfire.html

 

[joel ewing]

Thanks to all of you who responded and helped me with this puzzling event. I've printed your responses, and now can address my friends with good authority! Joel in Tucson

 

[Greg Campbell]

Joel, where did you see this? I was out on the SE side, close to SNP East, and saw lighning everywhere, but no eerie glow.

Did you get any pictures by chance?

Patrick is no doubt right about you seeing some form of St. Elmo's Fire.

-Greg

 

[joel ewing]

Greg, I live in Tortolita...if you know where that is. Actually, we're not a separate little town north of Tucson....we lost our long well-fought fight with the city within the past couple of years to become one. But if you don't....Tortolita is due north of Tangerine Rd. ....at the foot of the Tortolita mtns. My house is nestled right up against the Tortolitas...and if you took La Cholla Rd. straight north to where it dead ends agains the mtns. there...(although it doesn't cut all the way through..but you get the idea) that's where my pad is.
I've got a 2-story Santa Fe home. The entire 2nd. story is the master bedroom..and when you walk outside of the bedroom to our south...it's all decked for 180 degrees around. So I've got killer viewing to the due east (the Catalina mtns.) and due west (Marana / Tucson mtns.), and of course we can see all the way south past metro Tucson down to about Sahuarita on a clear day. It's a killer place to watch storms...especially lightning.
Where we were seeing this St. Elmo's / incredible glowing display appeared to be south of Tucson. We were looking due south from the 2nd. floor. CG's were just sticking the ground...and staying there for a long time too. We saw several strikes light up as if something caught fire as well, in addition to the St. Elmos. My guess it was around either the Indian res. where San Xavier mission is....or farther south.
Dude....it was an incredible show. I looked for anything about the glowing in the paper the next day (the Star..I didn't check the Citizen) but found nothing. Other people that worked with my wife did....so it definitely wasn't some illusion I was seeing.
Who knows.....if we ever get a real monsoon again....we might see it again too.