Community Collaborative Rain, Hail and Snow Network Community Collaborative Rain, Hail and Snow Network The Community Collaborative Rain, Hail and Snow Network, or CoCoRaHS, is a network of volunteer weather observers in the United States, Canada, and the Bahamas that take daily readings of precipitation and report them to a central data store over the internet. The network was started in 1997, in Larimer County, Colorado after a flash flood in Spring Creek killed five people and damaged structures in the city of Fort Collins, Colorado, including hundreds of millions of dollars in damage to the Colorado State University campus. The severity of the flood and its
Hail with air, wind, and interaction with rain and other hailstones can slow their descent through Earth's atmosphere. Severe weather warnings are issued for hail when the stones reach a damaging size, as it can cause serious damage to human-made structures and, most commonly, farmers' crops. Any thunderstorm which produces hail that reaches the ground is known as a hailstorm. Hail has a diameter of or more. Hailstones can grow to and weigh more than . Unlike ice pellets, hailstones are layered and can be irregular and clumped together. Hail is composed of transparent ice or alternating layers of transparent and