There should be lots of video on YouTube of transformer and power lines blowing if any anon wants to compare.
Strange thing, though, that arc dwarfed the height of the high tension line tower in front of it in one pic I saw on here. Those things are probably higher than 100 feet.
My guess? Godzilla. Kek.
Serious guess? Didn't Q mention something about dark eye or dark eyes in relation to the power grid?
No, no, no, no! DOD has studies that show that the worst thing that will happen to vehicles is that it will stall, and when restarted, the check engine light will stay on.
EMP effects are greatly exaggerated. So much so, it comes close to being fear porn. Do some research if you don't believe me.
Just did a half-assed dig on the fluids used to cool transformers. None contain copious amounts of sulphur, and are mostly normal hydrocarbons. That leaves electrical arc to explain the blue, or something else. Look how high those flames are, and they are blue. Voltage high enough to cause plasma? Looks an awful lot like the blue in cerenkov radiation.
Some anon who is good with photoshop/video editing should put in Godzilla on one of those photos/videos. Title it "found the cause of the transformer fires". Would be good for a laugh, I would think.