Moist air masses fed the heavy rainfall as they moved into the so-called ‘Flash Flood Alley.’ For every 1°F increase in temperature, there is about 4% more water vapor in the atmosphere

The Gulf, which borders Texas, has become significantly warmer in recent years due to climate change, Swain explained. This results in a very warm body of water that produces a lot of evaporation, releasing more tropical moisture into the air than seen historically.