Weather watchers seeking an outlet for their interest might consider joining CoCoRaHS, the oddly named but well-respected “citizen science” project that is adding to the nation’s understanding of precipitation, as well as predicting floods.

The program stands for Community Collaborative Rain, Hail and Snow network. It’s made up of close to 10,000 active volunteers around the country and in Canada who measure their backyard precipitation each morning – melting snow to get the “liquid equivalent” – and post the data to a public website.

New Hampshire now has close to 100 active volunteers, including a dozen or so in Hillsborough County – but none are in Bedford.

The goal of CoCoRaHS is to have at least one observer each square mile. It would require 9,350 people in New Hampshire.

You need to buy a specialized rain gauge, which costs about $28, and have a relatively uncovered place to put it so results aren’t swayed by rain dripping off leaves or roofs. And you’ve got to get up most mornings before 8 a.m. to input your data, although there’s no penalty for missing days.

This CoCoRaHS data augments more detailed collections made at a few hundred weather stations around the country, filling in holes and enabling better prediction of droughts and floods, among other things.

The group started in 1998 at the Colorado Climate Center at Colorado State University, after that area was hit by surprise flooding because a lack of such fine-grained rain measurements.

CoCoRaHS is now in all 50 states and Canada. Backyard depth measurements of snow have proved particularly valuable for estimation moisture in the environment. It also provides one of the few sources of hail measurements in the country.

For more information, visit cocorahs.org .

If you want to get details from a local volunteer, call David Brooks, who writes the GraniteGeek science column for The Telegraph of Nashua, at 594-6531.

– DAVID BROOKS, Staff Writer