In some cases, lightning can shoot from the ground up into the sky, resulting in an incredible tree-like lightning bolt. This is ascending lightning, a phenomenon rarely photographed.
Contrary to what many people think, lightning can go from the cloud to the ground as well as from ground to cloud. Lightning formation is still subject to many mysteriesand ascending lightning has been studied recently: it will have been necessary to wait for the development of photography and the multiplication of storm chasers so that real studies are put in place. American scientist and storm chaser Tom A. Warner recently made new discoveries on the phenomenon of ascending lightning thanks, precisely, to his shots: of the 776 photos of lightning that he captured, 41 show ascending lightning.
His photos and videos in slow motion have made it possible to highlight light the fact that ascending lightning occurs almost every time due to the presence of positive cloud-to-ground lightning nearby. lightning positive is the most dangerous because it has no, or almost no branching (unlike negative lightning), so all its power is directed to the same place. It represents only 10% of lightning, and in some cases, it is therefore accompanied near another lightning that goes from the ground to the sky.
The tallest buildings and mountain peaks are starting points
The change of electric field caused by thecloud-to-ground lightning positive is causing a tracer on a nearby peak or top. The tracer is a fairly weak electrical charge that advances towards an area of opposite charge, creating an ionized channel. The electricity from the storm generally triggers a negative charge (invisible to us) in the direction of the ground. Objects on the ground most often have a positive charge on their side, and since opposites attract, the object on the verge of being struck by lightning sends a plotter. When the two tracers meet, that of the object and that of the cloud, a return discharge appears from the ground towards the sky: this is the ascending lightning.
The phenomenon occurs most often with sharp and high objects, such as antennas on the rooftops buildings, or mountain peaks. During its ascent to the cloud, the lightning branches out into several branches, hence this spectacular tree shape. Ascending lightning propagates to a speed from 40 to 70 km/s at the start of their formation near the ground, then 500 to 1,000 km/s at altitude. The forming speed Lightnings ascending is such that it very often does not allow the observer to realize that he has just seen a flash starting from the ground. It is usually by looking at his photos or videos in slow motion that he realizes this.
Upward lightning also possible during snowstorms
Among the ascending flashes, we also find the two categories, the positive and the negative. The discoveries of Tom A. Warner also made it possible to show that ascending lightning could occur during snow stormsa particularly rare phenomenon: in this specific case, the lightning that goes from the ground to the cloud would form even without the help of a first positive cloud-to-ground lightning.
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