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Citizen Scientists Track Rain Drop by Drop

*Jim Ridgley checks his rain gauge outside his house in Frederick, Md.
Photo by Rebecca Jacobson.*

Inside Jim Ridgley’s living room in Frederick, Md., the fire station scanner chatters nonstop and the AM radio buzzes with weather reports. A hand-held ham radio sits by the easy chair in case Ridgley needs to radio in severe weather alerts to the National Weather Service’s Skywarn network.

At 8 a.m. each day, Ridgley checks the rain gauge in his driveway. The gauge is a clunky-looking thing on a wooden post discolored from the sun and measuring 14 inches in height. Back inside, he jots the reading in the margins of his morning newspaper and then enters them into an online database.

He’s not a meteorologist, and he’s not a climate scientist — he’s just a man interested in the weather. Retired now from a 50-year career as a firefighter, Ridgley feels he can still help protect against natural disasters by contributing “boots on the ground” observations for the weather service. Plus, he said, he enjoys doing it.

He reports his rain gauge findings to the network even on the driest days. “Zeroes are just as important to record as precipitation,” he said.

Ridgley is one of 15,000 volunteer members of the Community Collaborative Rain, Hail & Snow Network, or CoCoRaHS, a group of citizen-scientists in all 50 states who measure rain, snow and hail at their homes or schools. They report their findings to an online network, where the data is used by a variety of national and local services from meteorologists and the National Weather Service to insurance adjusters.

The network was started in 1998 after a storm flooded Fort Collins, Colo., and caused five deaths and millions of dollars in damage. On the radar, the storm didn’t look all that destructive. But to the surprise of meteorologists, the rain slammed the foothills and flooded sections of the city with as much as 14.5 inches of water.

It was just the sort of rainstorm that would have benefited from real-time data from residents on the ground, said CoCoRaHS coordinator Henry Reges.

“If people were aware of what was coming down and got the information out earlier, they could have saved lives,” Reges said.

Ridgley, a third-generation firefighter, has seen firsthand how quickly a little rain can become a flash flood.

Whether it’s a drizzle or a downpour, CoCoRaHS volunteers spring into action, entering their daily precipitation data and submitting severe weather reports. All members are required to buy a rain gauge like Ridgley’s; all are taught how to install it and how to read it. The volunteers become extra sets of eyes and ears who can help fill in the gaps — areas that weather stations don’t record — and even give early warnings about severe weather, Reges said.

“It’s like a picture. The more pixels you have, the better picture you get,” Reges said. In other words, more data from CoCoRaHS members means a stronger national weather database.

The National Weather Service, the National Oceanic and Atmospheric Administration, meteorologists, city planners, mosquito control, claim adjusters — they’ve all come to rely on CoCoRaHS data, Reges said.

James Zdrojewski, manager of the National Weather Service’s Cooperative Observer Network, said volunteers provide readings in places automated sites simply can’t reach. This can be particularly useful during severe snowstorms.

“Snow is extremely variable, even at nearby sites,” he said. “Millions of dollars can ride on it.”

Other than the purchase of a rain gauge, CoCoRaHS does not charge participants to join. In turn, the network offers educational online seminars to teach the public about snow, lightning, hurricanes and other types of storms. In Colorado, volunteers sometimes gather for “hail-pad-making parties.” A hail pad is a square foot of plastic foam covered in heavy-duty aluminum foil, and it’s used to capture, measure and study hail.

Nolan Doesken, state climatologist at Colorado State University and CoCoRaHS founder, said that although the group is “measuring like crazy,” CoCoRaHS is still desperate for more volunteers, especially in rural areas.

Reges hopes to double the size of their network this year. “Every data point we get is helpful,” Reges said. “We don’t want it to be a drudgery. We want to make this a fun project for folks.”

Volunteers range from retirees to schoolchildren. Some 200 schools across the country have entered data at some point for the network. Getting students involved teaches them how precipitation varies from block to block in their own community, said Noah Newman, education coordinator for CoCoRaHS. Plus, the data gets used by real scientists.

The volunteers also put a human face on the impact of severe weather, Doesken said, as nearly every disaster affects someone in the CoCoRaHS community.

“We can’t help but feel their pain,” he said in an email. “That gives it such a different and more personal feel. I don’t know how long we can maintain this sense of ‘family’ in this world of ours — but we’ll keep trying.”

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