CoCoRaHS (The Community Collaborative Rain, Hail and Snow Network) is a national volunteer precipitation monitoring network. This low-cost network of backyard rain gauge readers has grown to become a reliable nationwide source for daily precipitation measurements. With over 15,000 volunteers, this rich data set is used by hundreds of organizations from the National Weather Service to the USDA on down to local utilities, individuals and businesses. Beyond data collection, CoCoRaHS has also become an effective experiential learning program for enhancing climate and water literacy.

Twenty years ago, as our field focused on NWS Modernization and widespread technical advances (ASOS, NexRAD, and many other remote sensing technologies), one may have thought that there would no longer be a place for a force of citizens to manually measure precipitation. Yet, here in 2012, the role of citizen science networks is stronger than ever. As one of the major volunteer networks in the country complementing the historic National Weather Service Cooperative Program, it has enjoyed surprising success and good publicity, but has also encountered many challenges and obstacles. This presentation will look at how this "accidental" national observing system tackles a variety of challenges, sometimes successfully, sometimes not. Future plans and opportunities for integrating simple CoCoRaHS data resources with more advanced monitoring systems will be described.