The Community Collaborative Rain, Hail and Snow Network, or CoCoRaHS, is a network of volunteer weather observers in the United States, Canada, and the Bahamas that take daily readings of precipitation and report them to a central data store over the Internet. The program is an example of citizen science.

History In 1997, the network was started in Larimer County, Colorado, after a flash flood in Spring Creek killed five people and damaged structures in the city of Fort Collins, Colorado, including hundreds of millions of US dollars in damage to the Colorado State University campus.

The severity of the flood and its widespread spatial variability surprised meteorologists, and Nolan Doesken, a former assistant state climatologist for the state of Colorado, asked for precipitation measurements from private citizens in the area. About 300 responded to his emergency request for data. Said Doesken later:

Expansion to other U.S. States/territories and other countries The program was originally confined to Colorado (the first "Co" in "CoCoRaHS" stood for "Colorado" instead of "Community"), but began expanding to other states, first expanding to Wyoming in 2003, with the last expansion into Nebraska in March 2013. +Order of U.S. States Joining the CoCoRaHS NetworkOrder of addition to networkState/District (in descending order from first included to last included) Time when CoCoRaHS expanded to specified state/district1Colorado19982Wyoming20033Kansas20044New MexicoMarch 20055TexasApril 20056MarylandOctober 20057VirginiaOctober 20058District of ColumbiaOctober 20059PennsylvaniaOctober 200510IndianaDecember 200511MissouriMarch 200612OklahomaJune 200613MontanaDecember 200614IllinoisDecember 200615AlaskaDecember 200616NevadaMarch 200717WisconsinMarch 200718TennesseeApril 200719South DakotaJune 200720IowaAugust 200721North CarolinaSeptember 200722New YorkSeptember 200723FloridaOctober 200724AlabamaNovember 200725KentuckyNovember 200726OregonLate 2007, Early 200827LouisianaJanuary 200828New JerseyFebruary 200829South CarolinaMarch 200830Rhode IslandApril 200831GeorgiaMay 200832WashingtonJune 200833UtahJuly 200834MichiganJuly 200835MississippiAugust 200836CaliforniaOctober 200837North DakotaNovember 200838IdahoJanuary 200939OhioFebruary 200940MassachusettsMarch 200941VermontApril 200942ArkansasApril 200943West VirginiaMay 200944HawaiiJune 200945ConnecticutJuly 200946New HampshireJuly 200947MaineAugust 200948ArizonaSeptember 200949DelawareSeptember 200950MinnesotaDecember 200951NebraskaMarch 2013 +Order of countries and territories joining the CoCoRaHS NetworkOrder of addition to networkCountry/Territory (in descending order from first included to last included) Time of which CoCoRaHS expanded to specified country/territory1CanadaDecember 20122Puerto RicoJune 20133U.S. Virgin IslandsFebruary 20154The BahamasJune 20165GuamOctober 2022

Users

CoCoRaHS is used by a wide variety of organizations and individuals. The National Weather Service (NWS), other meteorologists, hydrologists, emergency managers, city utilities (water supply, water conservation, storm water), transportation departments, insurance adjusters, the USDA, engineers, mosquito control, ranchers and farmers, outdoor and recreation interests, teachers, students, and neighbors in the community are examples of people who use CoCoRaHS data.

Other programs In or around 2000, the National Weather Service Lincoln, Illinois independently began a similar program, the Significant Weather Observing Program (SWOP). CoCoRaHS data supplements the more rigorous data from the national program with increased spatial and temporal resolution. Real-time data is also provided by the Citizen Weather Observer Program (CWOP), whose users operate weather stations that automatically report over the Internet, and which supplements the more rigorous data reported by formal surface weather observation stations. The earliest and thus critically important for its long-term historical record from respective locations is the Cooperative Observer program of manually recorded daily summaries.

Sponsors The National Oceanic and Atmospheric Administration (NOAA) and the National Science Foundation (NSF) are major sponsors of CoCoRaHS and the Bureau of Land Management (BLM) is also a partner. Other organizations have contributed either financially or with supplies and equipment. Many other organizations and individuals have also pitched in time and resources to help keep the network up and running.

Forms Gregory Syroney with the Scioto County Storm Chaser Center, in Portsmouth, Ohio created the Significant Weather Report Form PDF File for CoCoRaHS Headquarters in Fort Collins.

Status As of 2015, all fifty states, the District of Columbia, and the Commonwealth of Puerto Rico participate in CoCoRaHS.

Canada In December 2011, the CoCoRaHS Canada network began in Manitoba following a massive flood in that province.

As of 2014, the network had expanded to the Canadian provinces of Alberta, British Columbia, Manitoba, New Brunswick, Newfoundland and Labrador, Nova Scotia, Ontario, Prince Edward Island, Quebec, and Saskatchewan, with over 20,000 participants as of March 2015.

See also Skywarn Safecast (organization)

References

Bibliography

External links

CoCoRaHS website and blog Twitter profile Facebook page NOAA Cooperative Weather Observer Program