Gauge the weather: NWS seeks volunteers for rain, snow network

Michelle Margraf with rain gauge
National Weather Service meteorologist Michelle Margraf shows a rain gauge used to gather data for the CoCoRaHS network, a system for collecting precipitation information.
Tim Nelson / MPR News

The National Weather Service wants you, especially if you live in western Minnesota.

The agency is trying to recruit more citizen volunteers to track precipitation in Minnesota through its Community Collaborative Rain Hail and Snow Network.

While it has a system of statewide data collectors already, there are gaps. Rainfall can vary widely over any given area, and having more measurements offers a more complete record.

The community network began in Colorado following a devastating flash flood, said NWS meteorologist Michelle Margraf.

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"Researchers found that there were a lot of people in their back yards measuring precipitation already, and they came up with a way that those people could share that information with the National Weather Service," she said.

That was back in 1998. Minnesota joined the network in 2009, and has hundreds observers who regularly track precipitation to improve forecasting. But they need more.

There are many parts of rural Minnesota where "we don't have good coverage for measuring snow and how much melts in the gauge," said Peter Boulay, a climatologist with Minnesota Department of Natural Resources.

While automated stations work well with rain, tracking precipitation is tougher in the winter. Observing snowfall is a very hands-on phenomenon. Machines aren't very good at it.

"Hard to find a replacement for a person going out there and measuring the snow," Boulay said.

Unlike other observation programs, the community network is a take-what-you-can-get system. It's strictly voluntary.

Map of CoCoRaHS stations
This map shows the concentration of Community Collaborative Rain, Hail and Snow Network stations in the Twin Cities. Weather officials hope to get more stations in Greater Minnesota to report precipitation and snowfall.
Minnesota DNR / Google

"We're just grateful for any report. You can report every day if you'd like to, just during the rain season or just during the snow season, or when certain events occur," said Margraf, the program's regional coordinator.

There are some requirements. Participants have to sign up on the website and do a brief training program, which can be done online. Observers have to buy a standard 4-inch diameter rain gauge, made to National Oceanic and Atmospheric Administration standards by a company in Fergus Falls, Minn. It costs about $35.

Russell Rogotzke has collected weather observations for decades on his farm near Springfield, Minn. Taking a few minutes to get the data and enter it on the web for the National Weather Service helps make forecasting more accurate, he said.

"When a lot of people record the data and send it in," he added, "they have data that was unheard of years ago."