Backyard could be part of record
Real-life weather data can help forecasters
Want your status as a weather geek to go down in history? You’ll go cuckoo for CoCoRaHS.
CoCoRaHS — also known as the Community Collaborative Rain, Hail & Snow network — has been collecting citizen science data on local weather conditions across the U.S. for more than 20 years. Ten thousand-plus observers, including close to 800 in Wisconsin, monitor and submit how much precipitation falls in their backyard, outside their place of work or at another spot in their community.
Weather can be highly variable, so this real-life data can help forecasters improve the accuracy of their reports. And once an observer submits for 100 days, the data becomes part of the nation’s official climate record, able to be used by weather and climate researchers.
“It’s a way for your backyard to have an impact,” said Kevin Erb, manager of the Conservation Professional Training program through UW-Madison’s Division of Extension.
But some Wisconsin counties have only a handful or fewer observers, rendering the data less useful. Erb, state climatologist Steve Vavrus and the National Weather Service are on a mission to recruit more.
Here’s what to know, and how to get involved.
How does CoCoRaHS work?
The weather monitoring network was born in 1998 at Colorado State University after a major flood in Fort Collins the year prior. Researchers realized they lacked real-time information to predict flooding, so they enlisted volunteers to put up rain gauges and regularly report precipitation.
It functions the same way today. Observers purchase a rain gauge (though it must be on the approved list for the program, because other gauges may not measure to the hundredth of an inch) and place it in their selected area. That area can’t be too close to trees, a house or anything else that might affect the amount of rain, snow or hail that falls. Every morning, preferably between 7 and 8 a.m., they take a look and submit the precipitation amount — even if it’s nothing — to cocorahs.org or the CoCoRaHS Observer app.
You can still participate if you don’t want to buy the gauge, Erb said. Observers can place a piece of white cardboard out in their yard and measure snow accumulation, for example. Those with a gauge can push it upsidedown in the snow, let the snow melt and report how much water was in the snowpack — helpful information for evaluating whether melting snow will cause flooding. People even make observations about how dry or moist the soil looks.
And you don’t have to commit to staying home 365 days a year to participate. Observers can check the gauge when they’re back from a vacation, for example, and clarify on the report that the rain fell over multiple days.
What difference do these weather reports make?
Weather can vary widely even across short distances. Erb said he works with farmers who swear they may get more rain on one of their fields than another one a mile and a half away.
Although weather radar provides a good estimation of what will happen, the farther you get from a radar site, the less accurate those estimates are, Erb said. Having a large network of observers posting real-life data can help forecasters make their reports more accurate — such as saying the heaviest rainfall is occurring in a certain part of a county, or that there’s flooding in a particular community.
On the flip side, reporting a lack of rain or snow can be proof of drought conditions. Wisconsin experienced a record drought last summer, and much of the state is in drought again now. If local governments apply for federal relief in drought or bad weather conditions, having multiple documented reports can help make the case, Erb said.
Wisconsin is working on building out another network of observations — the Wisconet, in which monitoring stations in each county will churn out data about temperature, precipitation, soil moisture and other conditions. The Wisconet and CoCoRaHS will work together to paint a more complete picture of weather across Wisconsin, Erb said.
How do National Weather Service forecasters use the data?
Forecasters look at CoCoRaHS observations every day, said Sarah Marquardt, a service hydrologist at the Milwaukee/Sullivan National Weather Service station.
They can be especially helpful during heavy rain or snow events, when observers can submit a “significant weather report” that is immediately transmitted to the weather service.
It can help forecasters make decisions such as whether to issue a flash flood warning, Marquardt said, helping her and her colleagues “when we need it the most.”
“Everyone benefits,” she said. “By getting information to us, we can get the information back out to the public.”
In times like those, she said, the oldfashioned gauges CoCoRaHS observers use actually perform better than fancier equipment. During a heavy rainfall, for example, automated rain gauges sometimes have a hard time keeping up.
How do you get involved?
To get started, visit cocorahs.org and click “Join CoCoRaHS.”
Erb said his ultimate goal is to have one person in every community consistently reporting precipitation. Right now, he’s far from it — particularly in northern Wisconsin.
Through the month of March, states compete with one another over who can recruit the most volunteer observers in a face-off called Precipitation Absurdity.
(It formerly held the name of a famous March sporting event, which is trademarked.)
Last year, Wisconsin racked up 128 new observers, Erb said, while Minnesota got over 500.
Believers in the states’ sports rivalry might want to expand their competitive streak to weather monitoring, too.
Madeline Heim is a Report for America corps reporter who writes about environmental issues in the Mississippi River watershed and across Wisconsin. Contact her at (920) 996-7266 or mheim@gannett.com.