I’m going to respectfully disagree on the beyond the horizon” bit in Mick’s first post, as the pics in the following post show the refinery clearly this side of the horizon. I don’t think ice crystal’s are necessarily involved in stack flare “light pillars,” which may need (and may have) another name if that one is specific to the ice crystal phenomenon.
My understanding is that you have a bright fire inside the stack intentionally burning off gunk that has accumulated inside ... Read even more