At least one death was confirmed on Thursday, Governor Greg Abbott announced.
In 30 minutes, the river rose by almost five meters, according to the US National Weather Service, NWS. People are being urged to seek higher ground.
A state of emergency has been issued for more than 6,000 people along the river, CNN writes.
Among those who died last year were about 30 children. Many of them were attending the Christian summer camp Camp Mystic, right next to the river.
