Seventeen years of measuring rain -- Experiences from CoCoRaHS (Community Collaborative Rain, Hail and Snow Network)

The quality, quantity and availability of precipitation data collected by CoCoRaHS volunteers, over time, has made it a primary data set for tracking and studying rain, hail and snow patterns across the U.S. It is... [ view full abstract ]

The quality, quantity and availability of precipitation data collected by CoCoRaHS volunteers, over time, has made it a primary data set for tracking and studying rain, hail and snow patterns across the U.S. It is nevertheless an ongoing challenge to recruit, train, and engage willing volunteers from all areas of the country in the process of manually observing and reporting precipitation. Furthermore, the playing field (society, demographics, technology and media) is continually changing. We will briefly describe how and why CoCoRaHS scaled up from a local community project to an international citizen science network and what we gained and lost in that process. We will look at participation metrics -- specifically recruiting and retention of volunteers. No single recruiting method has worked uniformly well in all parts of the country, and dozens of approaches have been successful to varying degrees. Partnering with the National Weather Service and their field offices across the country has been the single most effective mechanism for network expansion. Retention is more complicated since it is not just a function of "initial interest". About 65% of initial applicants engage in taking measurements, and of these, a much smaller percentage become long-term, year-round observers. Several retention metrics will be shown, and we will discuss how this information is used in program planning and implementation.