General Discussion

Flash floods happened before climate change kicked into gear but as the EPA wrote (before the Dark Ages)

Texas’s climate is changing. Most of the state has warmed between one-half and one degree (F) in the past century. In the eastern two-thirds of the state, average annual rainfall is increasing, yet the soil
is becoming drier. Rainstorms are becoming more intense, and floods are becoming more severe. Along much of the coast, the sea is rising almost two inches per decade. In the coming decades, storms are likely to become more severe, deserts may expand, and summers are likely to become increasingly hot and dry, creating problems for agriculture and possibly human health.

https://www.epa.gov/sites/default/files/2016-09/documents/climate-change-tx.pdf