CoCoRaHS Review

Farm Forum

Having recently received the bi-monthly newsletter for CoCoRaHS observers, “The Catch,” it seemed like a good opportunity to share some highlights of the 2014 year. CoCoRaHS,, originated in 1998 with the Colorado Climate Center at Colorado State University. A flood in the Fort Collins area a year earlier showed the need for localized precipitation information, which prompted the system. South Dakota joined the CoCoRaHS network in June of 2007, and currently contributes about 1000 volunteer observers to the nearly 20,000 observers across the United States and Canada.

For a volunteer network, CoCoRaHS observers have an impressive record. In 2014, 19,826 stations had at least one report, 4,387 new volunteers signed up, 3,594 stations reported every day or almost every day, 7,569 stations had at least 300 daily reports, and a total of 4,000,000 daily precipitation reports were posted during the year.

Of course the outlandish weather events are what get people’s attention. The most rainfall for 2014 was reported by an observer on the big island of Hawaii (station HI-HI-14), with 210.75”. The most rainfall in one day was posted by an observer in Baldwin County, AL (station AL-BW-45) on April 30 with 20.00” (35 CoCoRaHS observers reported at least 10” that day). The greatest one-day rainfall in California (during the drought) was 10.84″, in Nevada County, NE of Sacramento (station CA-NV-6). There were 11 days during the year where one or more CoCoRaHS observers measured 10″ or more of rainfall in a day, and 99 days where it rained at least 6″ somewhere in the country. The most prolific heavy rain producing states in 2014 were Florida and Texas (19 days over 6″) followed by Hawaii (12 days). Half of the states had at least one day where it rained 6″ or more somewhere in their state. The newsletter didn’t contain any notable snowfall amounts, which would have been interesting.

South Dakota has some extreme weather (it’s been pretty cold the last few days), but I think most of us can get by fine without that kind of notoriety. I’ve promoted the CoCoRaHS network numerous times in this column, and encourage people to become observers, especially if you can “fill in a hole” where there isn’t an observer. Joining (and reporting) is quite simple, just visit the website and click “Join CoCoRaHS” in the “Main Menu” on the left-hand side of the page. There is a simple, on-line form to fill out, and usually within a day, you’ll receive an e-mail with your username and password. One of the important parts of the application form to get correct is your location. In order for your station to show up in the right place on the map, GPS coordinates (longitude and latitude) are the most reliable. The only piece of equipment needed is a high capacity 4” rain gauge, which can be ordered from the website provided, or many counties have sponsors who provide gauges at no cost. If you have questions and/or need a rain gauge, contact your local area coordinator, the application form contains a link “List Coordinators,” where their contact information can be found. Not all of the contact information is current, but the state and regional coordinators can also help.

Many people, including myself, use CoCoRaHS information for a variety of reasons. It might be just to see how much rain various locations received around the area, or whether they would be able to do some field work that day on land they farm some distance away.