First description of a crown flash
Monthly Weather Review
first first
Not Applicable ()

An extremely rare meteorological phenomenon, crown flash, was first scientifically described in the journal Monthly Weather Review in 1885. It can occur at the top of thunderstorms and appears as a bright patch of sky not dissimilar to a sundog. Unlike a typical sundog, however, these features move and realign within seconds, forming beams and loops of light. The most likely explanation is that crown flash is caused by changing electrical fields within the thundercloud, to which plate- or needle-shaped ice crystals align, preferentially reflecting sunlight.

Due to the global emergence of camera phones, there are now several examples of amateur footage of this phenomenon on social media. The phenomenon is also known as a 'leaping sundog'.