The Community Collaborative Rain, Hail and Snow Network (CoCoRaHS) organizes volunteers in communities throughout the United States to collect and measure precipitation — rain, hail and snow — in their communities. You don't have to be a meteorologist -- you just need to have an interest in weather conditions and a desire to learn more about how weather impacts our region. Citizen volunteers are trained how to measure precipitation using a rain gauge and hail pad, record their data and report their measurements online. Many agencies rely on precipitation data collected by CoCoRaHS during and after rainfall and flood events to determine where the most rain has fallen and where the potential for flooding is greatest. CoCoRaHS’s volunteer precipitation reports help to fill in the gaps between official rainfall data collection sites in our region, such as the Harris County Flood Control District’s Flood Warning System, the National Weather Service’s climate sites, and the Lower Colorado River Authority’s Hydromet system. 

To join, visit www.cocorahs.org and click on the “Join CoCoRaHS” emblem in the upper right corner of the homepage.

An excellent example of CoCoRaHS in action is from March 20, 2013.  What appeared to be really heavy rain on the radar ended up measuring only a .25 inches of rain.  Hail cores made the radar appear "hot," but a network observer wasre able to report the ground truth.  Also in May of 2012, CoCoRaHS watchers recorded 11.19 inches of rainfall in Pecan Grove. The flood control district inspected the gauge and its surroundings to determine the validity of the report. It checked out and another station Pecan Grove recorded 10.70 inches. Without these observations we would have had to rely on radar estimates which were only showing 7 to 8 inches of rain.  You can see from these two example we need you to join the team. 

”Ground truth is always better than radar because it shows what is actually happening,” says Harris County Flood Control District meteorologist Jeff Lindner, who heads the Houston/Galveston region of the CoCoRaHS Network. “Texas can have incredible, locally intense rains that don’t always detect well on the radar and might go unnoticed without our CoCoRaHS observers.”