CoCoRaHS -- A Rich Resource of Precipitation Measurements in your Viewing Area

CoCoRaHS (The Community Collaborative Rain, Hail and Snow Network), celebrating its 10th anniversary in 2008, will be available in 34 states at the time of this presentation. Currently the network engages over 8,000+ volunteer observers of all backgrounds and ages to measure precipitation right in their own backyards.

Precipitation is measured using low-cost high capacity 4" diameter plastic rain gauges and Styrofoam wrapped in aluminum foil "hail pads". Thanks to the "low-tech/low-cost" approach, thousands of volunteers can afford to participate, giving the end user a large collection of data points that fill in gaps in many existing networks and data sets. Where feasible, CoCoRaHS is striving to achieve a station density approaching one observation per square mile providing exceptional detail on cumulative storm precipitation over populated areas. These observations are collected and made available on the CoCoRaHS website: www.cocorahs.org in map and table format.

The data are already being used daily by federal, state and community organizations and businesses for many resource management and hydrologic monitoring and predication applications. Many broadcast meteorologists are tapping into this rich daily-data set to help augment their broadcasts with precipitation measurements from their viewing areas. CoCoRaHS "Intense Rain Reports" and "Hail Reports" are used in "real time" by the National Weather Service in the issuing of flash flood warnings and severe thunderstorm warnings. While only providing once-daily and occasional event reports, CoCoRaHS does provide excellent observational consistency and accuracy including snowfall, depth and water content measurements, as well as the only comprehensive hail data currently being gathered in the U.S.