When outdoor warning sirens sounded across San Marcos on the night of May 26, some residents were left wondering what the alert was for.

The confusion followed the city’s first use of its newly repaired Outdoor Warning System in response to flash flood warnings issued by the National Weather Service, or NWS, according to a post on the city’s official Facebook page and city officials.

The system, which underwent extensive repairs last summer, is designed to alert residents to life-threatening emergencies, but the May 26 activation highlighted ongoing uncertainty among residents about when the sirens are used and what they mean.

The overview

According to the city website, the Outdoor Warning System is used to notify the public of three types of imminent threats: tornadoes, wildland fires, and public safety emergencies such as flash floods. Each type of threat has a unique siren tone to help residents identify the danger, according to the city’s website:
  • Tornado warning: A long, steady, single-pitch tone lasting three minutes
  • Wildland fire: Alternating high and low tones for three minutes
  • Public safety threat: A wave-like tone that changes pitch every 16 seconds for three minutes; this includes flash flooding, hazardous materials spills, or other urgent risks


More details

With another round of storms expected to move through the area on late May 28, according to a city Facebook post, city officials are urging residents to monitor local weather updates and be ready to take action if watches or warnings are issued by the National Weather Service.

San Marcos is no stranger to the dangers of flooding, according to the post, and city officials say the impact such events have had in the past underscores the importance of a reliable and clearly understood siren system.

Following the May 26 activation, some residents expressed confusion, as sirens are often associated with tornado warnings. In response, the city temporarily paused the system’s automatic alert feature to conduct a review, explaining why the sirens didn't go off in the morning of May 28 when another flash flood warning came from NWS. According to Public Safety Communications Specialist Russell Wilde, that feature has since been re-enabled, and the sirens are now fully operational.


“Our goal is to ensure that residents understand how to respond when they hear the sirens and to maintain trust in the system as a reliable tool for public safety,” Wilde said.

Next steps

Officials emphasize that sirens are only one part of a broader emergency communication strategy. Residents are encouraged to have multiple ways to receive alerts, including weather apps, NOAA weather radios, and local media, and to sign up for regional notifications through Warn Central Texas.