THE COMMUNITY COLLABORATIVE RAIN AND HAIL STUDY -- COCO RAHS

CoCo RaHS, the Community Collaborative Rain and Hail Study, is an "old fashioined low technology" approach to the very pressing challenge of accurate rainfall monitoring. CoCo RaHS currently consists of over 1000 trained volunteers ranging in age from youth to senior citizens. Volunteers measure and report precipitation on a daily basis to help meteorologists, hydrologists, storm water professionals and many others map and track storms and resulting precipitation patterns.

While many new hydrologic monitoring technologies are in use, this "old fashioned" approach is proving to have many advantages. Manual measurement generally exceed the reliability of automated gauges for storm total precipitation and hence serve as "ground truth" for any other sources of rainfall data such as flood warning system networks, radar estimates or satellite platforms. Due to the low cost, large numbers of reporting stations can be deployed, particularly over urban areas. The large spatial and temporal variations in precipitation that typify many storms continue to be an important challenge to improved modelling and prediction of runoff and flooding. The added bonus is that via internet communications, the hundreds of participants become true team members in this research and learn a great deal about both hydrology and meteorology.

Plans are to continue to grow and expand the program to an observing density of more than one observeration per four square kilometers over urban areas of the Colorado Front Range within the next 1-2 years, and as many volunteers as possible over rural areas including several adjacent states. The CoCo RaHS website, http://www.cocorahs.org, provides public access to all data collected and is the hub for communications, education and outreach.