As the investigation continues into whether local emergency officials in Texas could have done more to warn people of the catastrophic flash flood unfolding, a story at NBC News adds another piece to the puzzle. It notes that one town on the Guadalupe River, Comfort, used a newly installed siren to alert people to danger. Comfort is in Kendall County, about 20 miles from Kerr County, where multiple deaths occurred, and nobody died in Comfort. "Kerr County has no siren system despite years of debate, in part because some local officials felt it was too expensive to install," per the story.
However, it's not quite as simple as saying the siren saved lives. For one thing, it didn't go off until daylight Friday—see this video—when many residents were already awake and aware of the danger. Such sirens also are intended to alert people outdoors, not necessarily people sleeping indoors, and many of the victims in Kerr County were swept away before sunrise. Still, the story suggests sirens could become more common in flood-prone areas, perhaps with better links to weather warnings. An interactive graphic at the New York Times shows the river expanding dramatically in both counties.