National Weather Service United States Department of Commerce

Severe Thunderstorms, Heavy Rainfall, And Flooding Possible Over The Plains; Typhoon Bualoi Approaches The CNMI

A storm system will bring the potential for severe thunderstorms capable of damaging winds, large hail, and isolated tornadoes over the south central U.S. today. Heavy rainfall may also lead to flash flooding. The system will shift toward the eastern U.S. on Tuesday. Over the western Pacific, Typhoon Bualoi will intensify and impact the northern Mariana Islands early this week. Read More >

We need You! Join the CoCoRaHS precipitation observing team! 


What is CoCoRaHS?

The Community Collaborative Rain, Hail, & Snow Network (CoCoRaHS) is a nationwide volunteer reporting network that provides precipitation measurements for natural resource, education and research applications. The National Weather Service uses CoCoRaHS precipitation data daily in river forecast models, flood and drought forecasts, and precipitation and snowfall maps and tables.

CoCoRaHS (pronounced co-co-raws) allows observers to share their precipitation measurements via the Internet, which can be used by agencies who need accurate, real-time precipitation data for various purposes. The only equipment needed to join CoCoRaHS is a standard 4" diameter plastic rain gage (available for purchase through the CoCoRaHS website) and access to the Internet to enter reports. Observers can report precipitation daily or only on days when they are able to take measurements. CoCoRaHS observers can also send real-time severe weather reports to the National Weather Service (NWS); including hail size, flooding, storm damage, and excessive rainfall, which greatly assist meteorologists in determining the impact of storms on local communities.

The CoCoRaHS network is an invaluable tool for the NWS and other state and federal agencies to help fill-in the gaps due to a lack of available observation sites. This shortfall is mitigated by volunteers from across the nation. Precipitation, in both winter and summer, can have wide ranging values. The more people reporting these data can greatly assist the NWS in providing better forecasts and warnings. Volunteers are welcome from across both Colorado and Utah, and we always need more people to join.


Brief CoCoRaHS Introduction video Short Introduction to CoCoRaHS video
Getting Started training video New To CoCoRaHS? Need a refresher on Observing?
How to measure snowfall training video How to measure rain training video


For additional information on the CoCoRaHS program, to view CoCoRaHS data, or to join the CoCoRaHS team, visit the CoCoRaHS web site at