The storm system also produced several tornadoes.
Three tornadoes were reported in Oklahoma as the system moved into that state. A few homes were damaged, a tractor-trailer was blown over and power lines were toppled.
Flash flood watches are in effect until Thursday morning for Oklahoma.
The storm also has started moving into Arkansas, Missouri and Kansas. Flood watches are in effect for parts of those states until Thursday night.
Hermine packed a relatively light punch when it made landfall Monday night, and many Texas residents said they felt unprepared for Wednesday's sudden flooding.
Robbie Owens of CBS Dallas Affiliate KTVT, reports that the storm's leftovers also spawned several tornadoes near Dallas as they churned over the state. One strip mall sustained some damage.