March 29, 2016

Weather Service citizen science program
needs Outer Banks volunteers

The Community Collaborative Rain, Hail, and Snow network, or CoCoRaHS, is looking for new volunteers across North Carolina. The grassroots effort is part of a growing national network of home-based and amateur rain spotters with a goal of providing a high density precipitation network that will supplement existing observations.

CoCoRaHS (pronounced KO-ko-rozz) came about as a result of a devastating flash flood that hit Fort Collins, Colo., in July 1997. A local severe thunderstorm dumped over a foot of rain in several hours, while other portions of the city had only modest rainfall. The ensuing flood caught many by surprise and caused $200 million in damages.

CoCoRaHS was born in 1998 with the intent of doing a better job of mapping and reporting intense storms. As more volunteers participated, rain, hail, and snow maps were produced for every storm showing fascinating local patterns that were of great interest to scientists and the public.
Recently, drought reporting has also become an important observation within the CoCoRaHS program across the nation. In fact, drought observations from CoCoRaHS are now being included in the National Integrated Drought Information System.

North Carolina became the twenty-first state to establish the CoCoRaHS program in 2007, and by 2010, the network had reached all 50 states with nearly 10,000 observations being reported each day.  Through CoCoRaHS, thousands of volunteers, young and old, document the size, intensity, duration and patterns of rain, hail, and snow by taking simple measurements in their own backyards.

David Glenn, a meteorologist with the Weather Service in Newport/Morehead City who is also the state CoCoRaHS coordinator, says there is at least one active volunteer observer in Duck, Kill Devil Hills, Manteo, Buxton, and Frisco.

"We would love to increase volunteer participation in these locations and expand to include volunteers in Kitty Hawk, Nags Head, Wanchese, Rodanthe/Waves/Salvo, Avon, Hatteras village, and, of course, Ocracoke" Glenn says. "Precipitation can vary so drastically, even across short distances, which is why we need observers in these locations. We also do not have any CoCoRaHS volunteers across Mainland Dare or Hyde County."

Volunteers are required to have an official rain gauge, which they can obtain through the CoCoRaHS website ( ) for about $30 plus shipping. Besides the need for an official 4-inch plastic rain gauge, volunteers are required to take a simple training module online and use the CoCoRaHS website to submit their reports.

Observations are immediately available on maps and reports for the public to view. The process takes only five minutes a day, but the impact to the community is tenfold. By providing high quality, accurate measurements, the observers are able to supplement existing networks and provide useful results to scientists, resource managers, decision-makers and other users.

“North Carolina has one of the most complex climates in the U.S.,” said Dr. Ryan Boyles, state climatologist and director of the State Climate Office, based at North Carolina State University.  “Data gathered from CoCoRaHS volunteers are very important in better understanding local weather and climate patterns.”

“An additional benefit of the program to the National Weather Service is the ability to receive timely reports of significant weather (hail, intense rainfall, localized flooding) from CoCoRaHS observers that can assist forecasters in issuing and verifying warnings for severe thunderstorms,” says Glenn.

"One of the neatest parts of participating in the CoCoRaHS program," he adds, "is that the reports are not only seen everyday by folks like me at the National Weather Service, they are often stored and become part of the official record during significant weather events like winter storms and hurricanes.

To become a CoCoRaHS observer, go to and click on the “Join CoCoRaHS” emblem on the upper right side of the main website.  After registering, take the simple online training, order your 4-inch rain gauge and start reporting!

North Carolina CoCoRaHS can also be reached on Facebook and through Twitter.

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