Baton Rouge Mayor-President Sharon Weston Broome announced the fatality during a Thursday morning news conference. Fire Chief Ed Smith said the victim had been rescued from a car in a flooded area. No other details were immediately available.
Authorities also were investigating reports of possible tornado damage in the Baton Rouge area.
The state transportation department said some low-lying roads and underpasses were closed due to high water as a band of heavy rain moved across south Louisiana. There were numerous reports of flooded cars in Baton Rouge and Lafayette.
The Louisiana House and Senate convened late because of the weather on the final day of the 2019 legislative session.