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Put Daily Rainfall Observations Into a Nationwide Database

Join the CoCoRaHS network and put your daily rainfall observations into a nationwide database.

Do you check your rain gauge every day? Then here’s a feel-good job for you: Be a precipitation reporter for a national network called Community Collaborative Rain, Hail & Snow Network – CoCoRaHS for short.

This network of rain, hail, and snow observers is now 20,000 strong, and it is the largest such network of daily precipitation reporters in the country – maybe the world! Volunteer reporters put up a professional-grade rain gauge, check it every morning, and file a simple report online at the CoCoRaHS website ( Or, they can do it via the CoCoRaHS mobile app. 

These reports from across the country give climatologists the best view available of how much precipitation has actually fallen and where, says Henry Reges, the national coordinator for CoCoRaHS based at Colorado State University (CSU).

The program was borne out of tragedy, he explains.  

“In 1998, we had a flash flood here in Fort Collins, Colorado, that killed five people. That storm dumped over 14 inches of rain in 24 hours. But 5 miles away, it was just 2 inches.”

Lessons Learned 

That, he continues, taught two lessons. First, there is tremendous variability in the precipitation amounts that fall from showers and thunderstorms. Second, having reports of rainfall amounts is extremely valuable in anticipating outcomes. 

CSU meteorologists used the experience to launch what would become CoCoRaHS. They began signing up precipitation reporters across Colorado.

“Within a few years, the data became so good that other states wanted to join in,” Reges explains. Kansas and Wyoming added reporters in 2003. By 2009, CoCoRaHS had precipitation observers in all 50 states. Now, it operates in Canada and several Caribbean nations, too.

There’s plenty of room for more. “It’s like the resolution on a camera. The more pixels (dots), the sharper the photo. We’re always looking for more observers,” he says.

A dot map on the CoCoRaHS website shows that reporter gaps are most visible in the rural Midwest and South. “We’d love to have more farmers,” says Reges. “They depend on measuring rainfall every day, and they make excellent reporters.” 

He says the rainfall reports – including reports of zero precipitation – are used every day by weather forecasters, the insurance industry, recreation entities, and many others. 

“Many organizations pull data from the CoCoRaHS database every hour to get the latest reports,” he says. 

In cases of extreme localized storms, the network could help save lives, Reges says. One example is the flooding rains that hit Colorado in 2013. CoCoRaHS reports triggered warnings that ultimately saved lives.

Reges says when you see forecasts of river stages and flood levels on the Missouri, Mississippi, and Ohio Rivers – or most anywhere else – timely CoCoRaHS data is probably at work. 

Reporters do this on a volunteer basis and are not paid, except for the good feeling of being part of a nationwide effort. They are asked to purchase a high-precision rain gauge, check it every morning around 7 a.m., and file their observation online. 

If you can’t do it every day (vacation, for example), there is a provision for making a multiday report. 

“The website will talk you through how to sign up,” says Reges. “It will even help you find one of our 250 state and regional coordinators who can help.

“We love farmers, and we really, really need their help!” he says.

Henry Reges
Henry Reges shows the largest documented hailstone ever recorded – nearly 2 pounds and 8 inches in diameter recovered in South Dakota in July 2010.

How to order the rain gauge

The official rain gauge distributor for CoCoRaHS is Weather Your Way ( The company provides a wide range of weather and precipitation-measuring tools, including the 4-inch-diameter gauge recommended for reporters. It measures up to 11.5 inches of precipitation to the .001 of an inch. It sells to observers at a discounted price of $30.50.

Dust Bowl II?

Could droughty conditions that spurred the Dust Bowl ever happen again?

Daryl Ritchison thinks it could. “It’s not a matter of if; it’s a matter of when it will happen,” says the interim director of the North Dakota Agricultural Weather Network. During the 2017 growing season, North Dakota struggled through droughty conditions ranging from moderate drought in eastern areas to extreme drought in the southwestern part of the state. 

The good news is, even if it does, farming practices are much better today and can help protect the soil under droughty conditions, he says. 

The second wettest North Dakota summer on record occurred in 1928. Nearly the exact oppposite occurred in 1929. “In the spring of 1929, it just stopped raining,” Ritchison says. “At that time, it was the second driest year on record. There was no crop.” 

Matters improved, particularly in 1930 through 1933. “It was not phenomenally dry in eastern North Dakota,” he says. Each year, though, had a rainfall deficit.”

Then came 1934. “It was really dry,” says Ritchison. The National Oceanic and Atmospheric Administration proclaimed it the driest year of the 20th century. 

Surprisingly, this was followed up by a wet 1935 in North Dakota. “In fact, there was a surplus of water conditions. That’s how wet it was in 1935,” says Ritchison.

Unfortunately, drought returned in 1936 in North Dakota and didn’t level off until 1939, when more normal rainfall occurred.

All this helped fuel an exit of topsoil from the state, too. Typical is the 36 original inches of eastern North Dakota’s Red River Valley topsoil that’s now down to 18 inches. That’s partly due to a combination of 1930s drought combined with the excessive tillage of that era.

“Farmers back then were trained to pulverize the soil for good seed germination,” he says. “It amazes me to think of all the soil that North Dakota lost back then day after day with 10 to 20 mph winds.” 

Fortunately, farming practices are better these days. More and more farmers are practicing techniques like no-till and cover crops to protect the soil. “Good soil practices can protect the soil in dry years,” he says.

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