2021-02-05 Rime Ice Close-up Physics Photo of the Week February 5, 2021 Needles on Needles – Rime Ice It was a dark and spooky night a couple of weeks ago (Jan 12-13) in the Swannanoa Valley. A low-altitude dense fog had settled in. The fog did not reach the valley floor, but the base of the fog was rather low. The fog made the night very dark. We could see the direct light of houses on the valley floor from our windows, but distant glow from Swannanoa and Asheville in the sky were noticeably absent as well as houses at mid altitudes in the low surrounding mountains. Unusually dark. The temperature was also below freezing. The freezing temperatures caused the fog droplets to freeze immediately (the droplets were supercooled – liquid below the freezing point) when they came in contact with any obstacle forming rime ice. Click on the image to see a larger view of “Needles on Needles” - needles of frost on a clump of pine needles. Every little twig in the mountain-to