A sensor for measuring precipitation. Two buckets tip on an axle as they fill with water. One bucket empties as the other one fills. Each tip represents a calibrated depth of water over the collection area, such as 0.01 inches or 1 millimeter
The Flood Control District of Maricopa County, Glossary of Flooding Terms, AZ, USA 2009. http://www.fcd.maricopa.gov/Education/glossary.asp x, (ND/ Flood - Amer) {477}