Where’s it raining?

That question drives everything from weather forecasting to emergency response. And a decades-old citizen-science initiative driven by ordinary volunteers generates some of the nation’s unique — and useful — precipitation data. It’s called the Community Collaborative Rain, Hail & Snow Network (CoCoRaHS), a nonprofit network that works to measure and map rain, hail and snow. Although it began in Colorado, the network now has volunteers in all 50 states and even other countries throughout the Northern Hemisphere.

No hard-and-fast rules exist for who gets to participate in the initiative, and the organization encourages anyone who is interested to get involved. All you need is some training and the willingness to offer a daily observation of the area where you live.

Volunteers use low-cost, high-capacity rain gauges to make mini-weather stations. Then they monitor conditions and submit reports to the network.

CoCoRaHS also encourages volunteers to track one of the trickiest forms of precipitation — hail. Hailstorms can be hard to track since they are usually local and short-lived. Using homemade hail pads made of foam and aluminum foil, volunteers collect data on the number and size of hailstones. The numbers are sent directly to the National Weather Service for forecasting purposes.

The NWS isn’t the only group that benefits from the volunteer data. Everyone from insurance adjusters to farmers and scientific researchers uses the precipitation information.

And tracking precipitation can be lots of fun. The organization is active on social media. Some regions have regular get-togethers. Some classrooms even get involved. Want to get in on the rainy action? Head to CoCoRaHS.org to volunteer.