Crown flash

Common card · No. 463051

Crown flash is a rarely observed meteorological phenomenon caused by the effect of atmospheric electrical fluctuations on the alignment of ice crystals. It has been described as "the brightening of a thunderhead crown followed by the appearance of aurora-like streamers emanating into the clear atmosphere". The current hypothesis for why the phenomenon occurs is that sunlight is reflecting off, or refracting through, tiny ice crystals above the crown of a cumulonimbus cloud. These ice crystals are aligned by the strong electric field effects around the cloud, so the effect may appear as a tall (sometimes curved) streamer, pillar of light, or resemble a massive flash of a searchlight/flashlight beam. When the electric field is disturbed by electrical charging or discharging (typically, from lightning) within the cloud, the ice crystals are re-oriented causing the light pattern to shift in a characteristic manner, at times very rapidly and appearing to 'dance' in a strikingly mechanical fashion...

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