Colorado State’s Coco Rahs Program is Looking for Denver-Area Weather-Loving Volunteers to Help Analyze Current, Future Storms

As hundreds of statewide volunteers for Colorado State University’s Community Collaborative Rain and Hail Study, or CoCo RaHS, are busy collecting and analyzing precipitation data from this week’s blizzard, the program’s leaders are looking for several hundred more weather observers in the Denver-metro area. CoCo RaHS volunteers learn about weather from leading state climatologists and make a difference by providing decision-making information for industry, agriculture, home owners, utility providers, insurance companies, resource managers and educators.

"CoCo RaHS volunteers provide valuable information to researchers and water managers throughout the state," said Nolan Doesken, a research climatologist at Colorado State’s Colorado Climate Center and director of the CoCo RaHS program. "As Colorado continues to make important decisions regarding water use for the spring and summer, CoCo RaHS weather-watchers are making a big difference in how the state plans for and reduces its vulnerability to drought."

CoCo RaHS leaders will be recruiting Denver-area volunteers throughout the spring and will be conducting several information and training sessions in the region in March, April and May. Upcoming CoCo RaHS volunteer training sessions in the Denver-metro area, free and open to the public, include:

  • Saturday, March 22: 10:30 a.m.-12:30 p.m. at the Philip Miller Library in Castle Rock;
  • Saturday, March 29: 10:30 a.m.-12:30 p.m. at the Bear Valley Library in southwest Denver;
  • Saturday, April 12: 11 a.m. -1 p.m. at the Woodbury Library in northwest Denver;
  • Saturday, April 26th: 11a.m. at the Boulder Public Library-George Reynolds Branch;
  • Saturday, May17th: 11a.m. at the Louisville Public Library;
  • Saturday, May 5: 1-3 p.m. at the Bear Valley Library in southwest Denver;
  • Saturday, May 17: 11 a.m.-1 p.m. at the Woodbury Library in northwest Denver.

All training sessions have capacity limits. Spots can be reserved and directions obtained by calling the CoCo RaHS office during regular business hours at (970) 491-8545 or by e-mailing Chris Spear, training coordinator, at

CoCo RaHS is a project designed to include volunteers in a study of the complex weather patterns of rain, hail and snow. Each time a storm occurs in Colorado, volunteers take measurements of precipitation using backyard gauges provided by the Climate Center. Precipitation reports and observer notes are transmitted via telephone or the Internet to the Climate Center each day. Climate analysts process the data and prepare detailed maps showing rainfall patterns. Scientists and water managers study these maps to learn how storms developed and moved across the region and to make water-use decisions. CoCo RaHS information is updated daily and available for public access on the Web at

"The National Weather Service operates a small number of official measurement stations in Colorado but cannot offer a complete picture of statewide storm precipitation totals," said Doesken. "Results evaluated by CoCo RaHS’s large and growing number of volunteer weather watchers show a complete statewide picture of precipitation totals. Without this type of widespread data, appropriate, well-informed decisions could not be made regarding Colorado’s climate and water use."

Although CoCo RaHS is well established, more weather observers are needed throughout metro-Denver to accurately measure and describe storm patterns. By the beginning of summer, Doesken hopes to have one or more volunteers per square mile in the Denver area, more than tripling the number of weather observers in the region.

"This is science for the masses, and we could not do it without dedicated volunteers, who range in age from 6 to 90," said Doesken. "This project is as practically useful and popular as any science done at Colorado State."

Several government, research and private organizations use CoCo RaHS data for making informed decisions. For example, the National Weather Service uses the CoCo RaHS rain and hail data daily to augment their own measurements. The U.S. Department of Agriculture uses CoCo RaHS information to improve estimates of future crop yields. Teachers throughout the state use CoCo RaHS to help teach math and science to students.

The Denver Water and Urban Drainage Flood Control District as well as several other Front Range utility providers monitor CoCo RaHS information to verify rainfall situations that could affect their operations relating to water supply, wastewater treatment and stormwater designs. Colorado State’s CHILL Radar research laboratory uses CoCo RaHS hail reports to improve methods for tracking hail storms remotely. The U.S Bureau of Reclamation and the Northern Colorado Conservancy District both use CoCo RaHS data to determine how storm precipitation will impact water basins and irrigation demands.

"This is a community project that benefits the entire state, and anyone can help," said Doesken. "The only requirements are an enthusiasm for watching and reporting weather conditions and a desire to learn about the power and beauty of our natural world. And it only takes a minute or two a day."

To learn more about the project or to sign up to become a volunteer, go to the CoCo RaHS Web site at or call the Colorado Climate Center at (970) 491-8545.