State Climatology Office seeking volunteer precipitation observers

WISCONSIN – The Wisconsin State Climatology Office is seeking volunteer precipitation observers across the state to support a wide range of efforts, including evaluating long-term snowfall trends, monitoring drought conditions and tracking intense rainfall events.

Volunteers become a part of the Community Collaborative Rain, Hail and Snow Network, or CoCoRaHS.

“[CoCoRaHs] is a nationwide network…” said Amanda Latham, Climate Outreach Specialist for the Wisconsin State Climatology Office. “It’s people from all different backgrounds, all over the country, that volunteer to take daily measurements of rain and snow. … It’s a really great way for us to track precipitation across the state of Wisconsin and across the entire country.”

Data collected by volunteer precipitation observers is used to increase understanding of how precipitation impacts Wisconsin’s agriculture, water resources, recreation and other sectors.

Reliable measurements and “ground truth” observations also improve weather forecasting by providing the National Weather Service.

“It’s really important to have the kind of ‘ground truth’ to verify what’s happening,” Latham said. “The National Weather Service has tools like satellite radar and model data which helps them in their forecasting and give them a good idea of what they think will happen, but the last piece of the puzzle for them is the actual ground observations of what precipitation is actually falling and what has already fallen.”

Because Wisconsin’s weather can vary significantly from one location to another and official weather stations are not located everywhere, localized precipitation data is often limited. Volunteer observers help fill the gaps.

“Let’s say there’s a messy wintry system coming in. Some areas are supposed to get rain and some areas are supposed to get snow. CoCoRaHS’ observers put in their reports of, ‘Hey, I’m getting some snow at my place in northern Brown County’ whereas maybe southern Brown County is getting a little bit of sleet,” Latham explained. “That really helps meteorologists at the National Weather Service know what’s going on and then better their forecast as that event continues to unfold.”

Volunteers use a standardized rain gauge to ensure consistency among measurements, reducing discrepancies that can occur with different equipment.

This official network of volunteers allows the State Climatology Office and other weather and climate service providers to track precipitation events and place them into historical context.

“This really helps us at the State Climatology Office get a better idea of trends in Wisconsin’s weather,” Latham said. “There are official weather stations at many of the major airports in Wisconsin, but that’s only maybe one in every county. These CoCoRaHS observers really help fill in those data gaps so we have more data to work with to get a better idea of trends in how Wisconsin’s climate may be evolving or changing over time instead of just using those select data points at those official stations.”

Volunteers measure and report rain, hail, snowfall and snowpack depth (or liquid water equivalent). While daily observations are encouraged, those who can report occasionally are also welcome.

The process takes about five minutes per day and requires a standardized rain gauge, which costs approximately $45.00.

Those interested in becoming a volunteer observer can sign up through CoCoRaHS at www.cocorahs.org/Content.aspx?page=application.