Why We Started a Volunteer Rain Gauge Network

In the fields of meteorology and climatology there is a long and colorful history of volunteer participation in data collection and research.  Beginning with famous folks like Benjamin Franklin and Thomas Jefferson, and continuing today, individuals and networks of individuals have made large contributions to our knowledge and understanding of atmospheric process and climatic patterns.  Joseph Henry, the first Secretary of the Smithsonian Institution in the mid 1800’s helped implement a nationwide (mostly east of the Mississippi at that time) volunteer observing program to help document the climate resources of the early United States and begin  to test and evaluate weather forecasting methodologies.   By 1890 the U.S. Cooperative Weather Observer network was instituted and has been in place continuously under the direction of NOAA’s National Weather Service (formerly USDA’s “Weather Bureau”) ever since.    This network consists of thousands of participants representing almost every county and local area of the country.  With over 120 years of reliable temperature and precipitation data, it is possible to track the variations and trends in climate conditions across the nation.  The network was not established to identify or track climate change, but thanks to so many decades of faithful data collection it is being used extensively and successfully for those purposes.   

Motivated by a catastrophic localized flash flood in 1997 in northern Colorado, a new network of citizen volunteers of all ages was established focused on documenting local variations and patterns in precipitation.  With a focus on climate education, the Community Collaborative Rain, Hail and Snow network (CoCoRaHS) now has 16,000 active participants in all 50 states and parts of Canada    www.cocorahs.org  CoCoRaHS compliments the National Weather Service’s Cooperative network to provide enhanced climate monitoring nationwide.

This presentation will briefly describe the development of CoCoRaHS and will show precipitation patterns and variations.  Examples of ways CoCoRaHS is contributing to climate science will be shown including examples of ground validation of meteorological radar and satellite data and how higher resolution rain gauge measurements are aiding flood forecasting and water supply assessments.  Snow and hail data and drought impact reports collected by CoCoRaHS volunteers are also proving to be extremely beneficial.