CoCoRaHS 5 Year Milestone in Illinois

5th Anniversary of CoCoRaHS in Illinois

Every morning hundreds of volunteer rainfall observers in Illinois head out to check their rain gages, rain, snow, or shine, and report their information. The Community Collaborative Rain, Hail, and Snow (CoCoRaHS) Network will mark its fifth anniversary in Illinois in December 2011.

CoCoRaHS is a grassroots volunteer network of backyard weather observers of all ages and backgrounds working together to measure and map precipitation (rain, hail and snow) in their local communities. The program started in Fort Collins, Colorado in 1998 and now exists in all 50 states and the District of Columbia. More than 10,000 volunteers participate nationwide. Volunteers enter their observation on an interactive web site, and observations are immediately viewable on maps or in tables. CoCoRaHS observations can be viewed at

There are currently more than 500 observers across the state of Illinois making and reporting daily rainfall and snow observations, supplementing the observations made at airports and by NWS Cooperative Observers.  These observations are used every day by the National Weather Service, private meteorologists and climatologists, the media, civil engineers, municipalities, farmers, and many others, including the general public. 

In the past five years Illinois observers have submitted more than 533,000 observations. Special reports on hail, heavy precipitation, and other weather events are relayed to the National Weather Service and used to monitor flooding potential, severe thunderstorms, and winter storms, and other significant weather events. Among the notable weather events that CoCoRaHS observations have helped document in Illinois the flooding rains associated with the remnants of Hurricanes Gustav and Ike in 2008, and the blizzard of February 1-2 of this year.

CoCoRaHS is looking for additional volunteers throughout the United States, not just in Illinois.  Additional volunteers are needed in Iowa and Missouri.  To find out more about this exciting program or to join, visit and click on the “Join COCORAHS” link on the web page.

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