These unusual looking growths of frozen water resulted when my pickup truck traveled through a winter storm in Denver, Colorado . At speeds from 30-60 mph (48-96 kmph), water accumulated and froze layer by layer on the side of the truck. As snow on the road melted due to the heat retention of the asphalt (and perhaps because of the spreading of road salt ), it splashed on the sides of the truck. Sub-freezing temperatures froze this dirty water and, with the help of gravity and wind, formed the odd layered shapes. These barnacles persisted for several hours before finally disappearing later in the day as temperatures climbed above freezing. Photo taken on February 26, 2015.