Washington is the latest state to join a rapidly growing network of volunteer rainfall observers across the country. As of June 1, Washington state became part of a growing national network of volunteers who collect local weather data.

The Community Collaborative Rain, Hail and Snow (CoCoRaHS) Network enlists volunteers to take daily rainfall measurements and report them to the CoCoRaHS Web site, www.cocorahs.org.

“These measurements provide an instant look at statewide patterns of rainfall that can help in weather forecasting, disaster management, drought monitoring and research,” said one of the state coordinators, Josiah Mault, of the Office of Washington State Climatologist at the University of Washington.

“Observers can send intense rain reports that are disseminated directly to the meteorologists at the National Weather Service, which will be crucial during flash flood events,” said Jeff Michalski, a meteorologist at the National Weather Service in Seattle.

On the other extreme, the real-time reporting will augment the NWS’s Cooperative weather-observing program in providing better real-time drought diagnosis, says State Climatologist Philip Mote, the other state coordinator.

CoCoRaHS, based at Colorado State University, was officially launched in Washington on June 1. It was organized by a group that includes the Office of Washington State Climatologist at UW and staff from the four National Weather Service forecast offices covering the state.

Volunteers who want to become observers must purchase a standard four-inch rain gauge for about $25 and attend a training session. Details about equipment and training are on the Web site.

“In the few days since the program began in Washington, we already have dozens of people signed up to be observers, just from word of mouth,” said Ted Buehner, warning coordination meteorologist at the Seattle weather service office. “People love the weather, and this is a great way to get involved — you can immediately see your measurement on the state or national map.”

Robin Fox, weather service forecaster in Spokane, said official rain gauges can be as much as 50 miles apart over widely varied terrain.

“You can miss a lot of data that way,” Fox said. “CoCoRaHS fills in the gaps of the current observation network.”

Ellie Kelch, another weather service forecaster in Spokane, added, “The additional precipitation data collected will allow scientists to better understand micro-climates across the state and greatly assist meteorologists in the forecast process.”

More information is available at www.cocorahs.org or climate.washington.edu.