The most common method of measuring rainfall is to use a container with a flat bottom and straight sides. While this type of container can give you a general idea of how much rain fell, it is difficult to determine precise rainfall or to record very small amounts of precipitation.

Because of this more sophisticated instruments, known as tipping buckets are used to more precisely measure Charlotte area precipitation. The rainfall is collected by a cylinder, 8 inches in diameter, and funneled to one of two small "buckets" on a fulcrum.

The two buckets are balanced (somewhat like a sea-saw) and each holds .01 inch of water. When one bucket fills, it tips down and is emptied while the other bucket fills with rain water. Each tip of the buckets causes the device to record an increase of .01 inch of rain.  This data is then transferred using the ALERT system to base stations where the information is made available throughout offices in the Charlotte area.  Rainfall data is also transferred to our Interactive Mapping web site, where you can view data from any of the 73 rain gauges.  For more information, please contact Amy Rockwell, arockwell@ci.charlotte.nc.us , 704-336-5779.

Factors such as wind, buildings and trees can modify the amount of precipitation that reaches a rain gauge.  Because of this gauges are typically placed on top of buildings and other elevated structures.