The war of the worlds has begun! Because of their rarity and unusual appearance, fallstreak holes, or punch hole clouds, are often attributed to UFOs because they form as large circular gaps in cirrocumulus or altocumulus clouds. They form in these high to mid-level clouds which are comprised of tiny water droplets that are below the freezing temperature but have not yet frozen (called supercooled water droplets). Airplanes passing through the cloud help the supercooled water droplets freeze. Air expands and cools as it passes over the wings and the propellor blades, decreasing the ambient temperature just enough to allow the droplets to freeze. The ice crystals grow and start to fall, while causing the water droplets around the ice crystals to evaporate. This leaves a large hole in the cloud with brush-like streaks of ice falling below it.
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