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 the hail to the radar, and the echo is further away from the radar than the actual location of the hail on the same radial path, forming a cone of weaker reflectivities. More recently, the polarization properties of weather radar returns have been analyzed to differentiate between hail and heavy rain. The use of differential reflectivity (formula_1), in combination with horizontal reflectivity (formula_2) has led to a variety of hail classification algorithms. Visible satellite imagery is beginning to be used to detect hail, but false alarm rates remain high using this method. The size of hailstones is best determined by