This scene captures a rare atmospheric phenomenon: an anvil-shaped cumulonimbus cloud crowned with a thin, iridescent layer. The colors appear when sunlight scatters through microscopic ice crystals at the cloud’s upper boundary, producing a spectrum similar to a rainbow but formed by diffraction, not rain. What looks dramatic is simply the physics of light interacting with a rapidly rising storm column at sunset. | AstroNature

IRIDESCENT LENTICULAR CLOUD — RAINBOW HALO OVER THE PEAKS A bright sun, a smooth “lens” cloud, and suddenly the sky shows oil-slick rainbow bands wrapped around the light. From the mountains it looks like a glowing ring—clean, sharp, unreal-looking—but it’s just perfect air perfect ice crystals lining up at the right moment. This effect is usually cloud iridescence: tiny, similarly sized water droplets or ice crystals in a thin cloud diffract sunlight, separating it into pastel/rainbow colors. L

IRIDESCENT SKY BURST Rainbow colors… 📍 Alaska (Fairbanks area) This is cloud iridescence .. when sunlight passes through tiny water droplets or ice crystals and the light spreads into bands of color (like a natural prism). It usually shows up near sunrise or sunset, especially when the clouds are thin and high. | AstroNature