Splung.com Physics Forum

[bronyaur]

Hi All,

While travelling in northern Italy last year I stopped in a small town in the Alpine foothills/Dolomites. Every night like clockwork there was a huge lighting storm and so I began filming and trying to take photos of the lighting.

During filming one night I captured the images below, obviously one is a normal lightning strike but one appears to be some sort of odd strike or discharge which didn't come from the sky but from the mountain ahead of me and then 'struck' right below the window I was looking out of.

These are screen grabs from and so the image quality isn't great, but can anyone tell me what is happening here?

Thanks in advance

[hepcj]

Firstly, thanks for posting your photographs, they are very interesting. The lightning that you say is coming from the mountain probably isn't coming from the mountain but is coming up from the ground near you. This a sort of corona discharge which can occur when lightning is about to strike.
Before the lightning strikes, high speed photography has shown that a dull leader stroke comes from the cloud making a ionised path of air for the charge to follow. Before it makes contact with the ground, the intense electric field can create a number of connecting ionised paths from the ground that try to make contact with it. One of them will successfully make contact and allow the huge amount of charge to flows from the earth to the cloud creating the bright lightning bolt.
I think this leader stroke from the ground is what you could have captured in your photographs.

[bronyaur]

That's very interesting. Thank you very much for the reply.