Automated Local Evaluation in Real Time (ALERT)
The District operates and maintains a network of real-time sensors used to collect hydrometeorological data. This network provides information to county personnel and other agencies about precipitation, stormwater runoff, and weather conditions affecting our regional watersheds.
Using radio telemetry, sensors report data in the National Weather Service Automated Local Evaluation in Real Time (ALERT) format. This type of network is commonly referred to as an ALERT system.
ALERT system sensors are event driven and transmit data in real-time to base station computers at the District's office and the Tucson National Weather Service office. Event driven real-time transmission, means that transmission of data occurs immediately as data is collected at field sites.
Data collected by the ALERT system is used by the National Weather Service to assist in issuing flood watches and warnings and to ground-truth radar determined rainfall estimates.
ALERT data is important to the District in providing for public safety. Data is collected primarily to detect situations that can lead to flooding. Data is also useful in reconstructing storm events and thus is of interest to a wide range of public and private users.
Currently, the ALERT system includes 93 precipitation, 36 stream, and 4 weather station sites located in Pima and adjacent counties.
VIEW ALERT SENSOR DATA. Data is provided for current and recent historical periods.
The links below provide additional information about the District’s ALERT sensor network and the data collected.