The phrase describes a vivid and dramatic atmospheric condition. It suggests a sky intensely colored, transitioning from deep reds to areas of stark darkness, and carrying a sense of untamed, almost violent, energy. This could, for example, depict the moments immediately following a volcanic eruption when ash and gases saturate the atmosphere.
Such phenomena, whether naturally occurring or induced by external events, have historically evoked strong emotional responses. They can be associated with both beauty and foreboding. Observing these intense atmospheric states can provide valuable data regarding the composition and dynamics of upper atmospheric layers, and offer insight into meteorological and geological events.