But Kerr County officials took nearly six hours to heed this call.
"The Guadalupe Schumacher sign is underwater on State Highway 39," the firefighter said in the dispatch audio.
"Stand by, we have to get that approved with our supervisor," a Kerr County Sheriff's Office dispatcher replied.
The first alert didn't come through Kerr County's CodeRED system until 90 minutes later.
When CodeRED was first introduced by Kerr County and the City of Kerrville in 2014, a government press release claimed it could "notify the entire City / County about emergency situations in a matter of minutes.".
The IPAWS system allows local officials to broadcast emergency messages and send text blasts to all phones in the area.
"It's just another avenue for us to notify people when we have an emergency," replied Emergency Management Coordinator William "Dub" Thomas. »