Weather volunteers help improve local precipitation records

Volunteers with The Community Collaborative Rain Hail and Snow Network (CoCoRaHS) record backyard rainfall and snowfall across North America and submit those hyper-local readings online; agencies including the U.S. National Weather Service and conservation authorities use the data.

Across North America volunteers are measuring and recording precipitation from their own backyards. They belong to The Community Collaborative Rain Hail and Snow Network (CoCoRaHS), founded in 1998 at Colorado State University. Many volunteers in Ontario and elsewhere submit simple measurements online using basic tools. The group’s hyper-local data helps fill gaps between official weather stations. Key facts: - CoCoRaHS is a volunteer network founded in 1998 and now includes thousands of observers across North America. - Volunteers use basic equipment such as a clear plastic gauge, a ruler and simple household items to measure rain, snow and snow-water equivalent. - The data are reported online and are used by organizations including the U.S. National Weather Service, conservation authorities and farmers. - Former meteorologist John MacPhee noted that official stations can be far apart and that backyard readings help capture local variation and snowfall details. - London, Ont. volunteer Joris Van Daele records measurements and reported nearly 40 centimetres of snow in one part of the city while another area recorded about 15 centimetres, illustrating local differences. Summary: Volunteers with CoCoRaHS provide hyper-local precipitation readings that supplement official station data and can inform agencies monitoring rainfall, snow and flood risk. More information about CoCoRaHS, including interactive maps of local precipitation and resources for prospective volunteers, is available online.