Historically, Texas is flood prone. 125 years ago in 1900, before air conditioning even existed, over 8,000 Texans were killed in the Great Galveston Flood.
Granted, that was a hurricane related event, but when the ground is already saturated with rain (as it has been over the past several weeks), and then we get a downpour, Texas floods, especially around rivers like the Guadalupe.
We saw this with:
1913 Brazos River flood (284 fatalities)
1921 Thrall flood (215 fatalities)
1957 floods (5 fatalities)
1998 south-central Texas floods (31 fatalities)
2015 Texas–Oklahoma flood and tornado outbreak (30 fatalities)
2017 Hurricane Harvey (107 fatalities)