I've noticed this in a hard snowstorm. You can hear the discharge clearly as a crackling sound and sometimes see a blue light. Corona discharge is an everyday phenomenon you're well familiar with. Copiers and laser printers, for example, contain a thin high-tension thread that charges the paper with corona. It's the same glow you see in fluorescent tubes and neon signs.
Corona also develops around pine needles, masts, and lightning rods during thunderstorms.
It's called St. Elmo's Fire when it occurs naturally. There is always a small amount of corona discharge going on, he says. The presence of moisture simply magnifies the effect. The arrow points to the energized wires, which are likely places for corona discharge to occur.