Central Texas, and more specifically the Hill Country region, are known for being prone to major floods. With one of the highest risks for flash flooding in the country, the area is referred to as the flash flood alley, according to the Lower Colorado River Authority. This is caused by a combination of steep hills and arid soil that water tends to run off quickly, funnelling water rapidly into rivers during rainstorms.
The Guadalupe River and surrounding rivers in the region have flooded multiple times in recent decades, often with deadly consequences. This includes flooding in July 1987 that killed 10, flooding in October 1998 that killed 31, flooding in May 2015 on the nearby Blanco River that killed 13, and flooding just 3 weeks earlier in nearby San Antonio that killed 13.
Kerr County lacked a flood warning system. In 2016, the then-sheriff of Kerr County advocated for such a system, including sirens. In 2016, a county commissioner noted that Kerr County was "probably the highest risk area in the state for flooding". Discussions about funding and constructing a system continued on and off until at least 2021. The current Kerr County judge, Rob Kelly, said that the lack of a warning system was due to its high cost and claimed that residents were resistant to the idea for that reason.
According to CNN, intense rainfall across the United States has greatly intensified in recent years due to global warming, as a warmer atmosphere can hold more moisture. According to Climate Central, San Antonio rainfall intensity has increased by 6% since 1970 while Austin's has risen by 19%, meaning that more rain is falling in a given hour now than it was decades ago.