Green and Blue Sky-Flashes in Tulsa on June 18, 2023

[gdlewen]

As the line of severe thunderstorms passed through Tulsa early this morning, there were several instances of blue and green-blue flashes visible. I initially thought they were power line flashes, and given the number of power outages throughout the area, that may well have been the case. However, just about every 4th or 5th instance looked to be blue or cyan intracloud lightning with no evidence of any ground-contact. Very pretty. The majority of the lightning flashes were white in color.

The image below is an example of a blue flash, looking southwest towards West Tulsa. The color recorded by the camera in this case is fairly true, and the brightest part of the flash was close to the ground. So, I suppose this may have been a power-line flash. (Having never seen a power line flash in person, I really have no basis for comparison.) I will look at some of the other pictures I took and if there is anything interesting I will add them here.



(Note: I am having a wee bit of an issue with terminology. On the one hand, there is the "power line" flash but then, of course, the total lighting event, including the various leaders and return strokes, is also called a "flash". It can get confusing.)

 

[gdlewen]

Adding a juxtaposition of successive pictures, one with a clear power line flash and one with intracloud lighting for comparison. The background light to the left in each is Tulsa city lights plus any intracloud lighting which occurred during the exposure. The IC lightning in the RH image has a distinct violet tinge (with which I'm sure we are all familiar.) It's pretty clear the blue color is not an artifact of the imaging process.

 

[gdlewen]

Last post, I promise. Juxtaposed images a bit later, showing the blue lightning flash does not appear to have an origin near the surface. At this point, the brightest flashes are all blue. Any "normal" IC lightning is dimmer, with only a hint of violet tinge. I will say that this blue flash appeared to have more of a cyan hue than is represented here, but unless someone really cares, I don't want to delve into the minutia of processing the raw images to correct any differences with my perception. (I'm not sure I could do it anyway.)