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How Rain Gauges Work

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

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

Rain Gauge

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.  

Data from rain gauges is transferred in real-time using the
ALERT system. The data is sent in real-time to the U.S. Geological Survey and to Charlotte-Mecklenburg Storm Water Services.

Routine rainfall data is recorded in five minute intervals. An alert is triggered when the intensity or amount of rain exceeds a pre-determined level. If an alert level is reached, the data is also sent to the National Weather Services.

Data is also transferred to our Interactive Mapping web site, where you can view rainfall amounts from any of the 73 rain gauges in Charlotte-Mecklenburg. 

For more information, please contact:
Samantha Willis at 704-336-5780 or
Josh McSwain at 980-314-3214​