As Harvey stalls over southern Texas, Houston is starting to feel the full impact of his rains. Many parts of the flood-prone city are already under water and numerous water rescues are under way.

Devastating.

https://twitter.com/davideblack/status/901817726750089216

Houston, Texas freeway sign nearly submerged amid extreme flooding from #Harvey: https://t.co/JZvofyopoP pic.twitter.com/rInVl4Wxba

— ABC News (@ABC) August 27, 2017

What a mess! MRT: via @KVUE: TV station KHOU #Houston forced to evacuate as station floods. #Harvey pic.twitter.com/InGUTltN7v

— Steve Rudin ABC7 (@SteveRudinABC7) August 27, 2017

https://twitter.com/maurygarcia92/status/901826208928866305

Aerial video shows Buffalo Bayou Park in Houston as Harvey causes severe flooding in Texas https://t.co/iJHbYTFT7I
Video via @avmidas pic.twitter.com/cVV8fI63fs

— NBC News (@NBCNews) August 27, 2017

Rescue in downtown #Houston @NBCNews pic.twitter.com/ICvYl5iE5s

— stephanie gosk (@stephgosk) August 27, 2017

Drone footage shows destruction left in the wake of Hurricane Harvey in Rockport, Texas. Read the latest here: https://t.co/iJHbYTFT7I pic.twitter.com/e4X6lm21DC

— NBC News (@NBCNews) August 27, 2017

And the mayor has good advice for those who find themselves in trouble:

"Do not go up in the attic unless you know there is an exit out," Mayor Turner says during Harvey update https://t.co/WZP2arvuWh pic.twitter.com/BumWF3Bw4Y

— CBS News (@CBSNews) August 27, 2017

FEMA is saying they will be in the area for years helping residents to rebuild and recover.