This is probably the most insane video I've seen of a close strike. It was filmed by two friends here in Darwin whilst chasing rural. What is significant, and which ultimately swayed my decision re standing out in the open whllst photographing lightning is the info gained from experts on the video.
I sent this video to Tom Warner in the US, who is a Phd in lightning physics and assisting me in my own research. What he found out is that there was an audible pop just prior to the actual strike grounding. Colleagues of his determined that this popping sound was in actual fact an aborted upward leader discarded by the downward leader channel to complete the connection and the location of this upward leaders was in fact the barbed wire fence in front of the photographer! She was milliseconds from being struck. Period.
You can see the raised dust from the actual strike grounding in the field…insane.
This video should highlight the real danger of standing anywhere around a thunderstorm in the open, regardless of where you are. Upward leaders from ground originate from anything and anywhere….you cannot see them and are rarely captured.
The scientists who viewed this footage agreed that the photographers WERE the initial targets for the leader, but the leader from the fenceline was rejected for a leader behind the tree. The pop you can hear prior the strike is weak thunder produced by the upward leader.
|Close positive CG!|
Just to add something to this…(photos courtesy Jacci Ingham)
There was a storm set last week here in Darwin and about 15 strikes eminated from a region close to the top of the storm. Now, general concencous is that all lightning coming from the tops of storms is + in polarity. This is not so due to not knowing the actual polarity of the entire storm itself at the time. I have mentioned somewhere here that storms are typically +. – and + in polarity. Bolts from the Blue daytime or night are concieved to be + in polarity. The images above (used with permission) was one of several taken by chasers and myself around the rural area. There was some heated debate about whether or not this is a positive strike or negative strike. After much arguing with nameless people and information from experts in the US, this image, and the six I sent ( of crap quality due to being at work and distance) revealed they are in fact negative strikes. Althogh they appear to be from the top of the storm, in fact they are exiting the central region of the storm which is the negative pool of charge.
Thunderstorms can and do change polarity from tripolar to unipolar and bipolar and inverted polarity. One strike can change the electrical field surrounding a storm and then return it to the norm. So for information sake, any large dog leg you see may well not be positive in charge Generally positive charged strikes are in the dissipating stage of the storm where the net negative pool is diminished through lifecycle of the storm and the only charge left is positive aloft. But bear in mind that different storms carry differing charges…location, storm type, atmospherics etc all play an important role as to what the storm will produce lightning wise. Winter storms generally are + charged, whereas sumer storms are the opposite. Less than 10% of lightning is positively charged worldwide, so they are not that common.
i was sent a Google map overlay with lightning strike data from Tom Warner re the night in question re these storms and they were all negative strikes with only a few positive types recorded by WLDN. He was a little suspicious, but agreed that the majority of the strikes were negative at that time re the photo.