What causes heat lightning?

[ticka1]

Is it always orange/yellowish in nature when its visible in the nighttime skyline? Saw some the other night and it was awesome - never had I seen the orangish glow on the lightning bolts before.

[Coriolis]

Ticka -

Heat lightning is light reflected by clouds from lightning in thunderstorms that are too far away for the thunder to be heard.

Heat lightning is simply ordinary lightning from thunderstorms far away. On a clear night, lightning flashes from a distant storm can be seen (sometimes)hundreds of miles away. Got it's name because of it is usually seen on hot summer nights - when thunderstorms are common.

As far as the color - "ask the experts".

Jim

[Richblue2]

Very cool.

Could the orange color be from the refraction? Like the sun getting more red as it sets.