Tropical storm Harvey continues to ravage south East

Texas, as the state's governor orders 1,000 more

National Guard members to help.

This morning, the US Army Corps of Engineers

is also expected to release water

from two reservoirs in an attempt

to protect downtown Houston.

CBN's Jenna Browder has the story.

JENNA BROWDER: Harvey has Houston under siege.

Torrential rains are engulfing the country's fourth largest

city as rising water chases thousands

of people to higher ground.

RESCUE WORKER: We got you.

We got you, don't worry.

JENNA BROWDER: Rescues continued overnight.

Dramatic moments, like this one, caught on camera.

CIVILIAN 1: We need help in fifth ward.

We need people here to evacuate people.

Get people here now before they die.

JENNA BROWDER: With more than 56,000 calls

in less than 24 hours, the 911 system is being overrun.

Many people say they can't even get through.

The geography is a big part of the problem

as rain water is forced onto the streets,

then into bayous easily overwhelmed by heavy downpours.

Buffalo bayou runs through the middle of Houston

and looks like this.

15 feet over flood stage.

A level never seen before.

In league city, southeast of Houston,

an astounding 30 inches of rain has fallen.

And the storm is not letting up.

Forecasters say some areas could see as much as 50 inches

before it passes.

An event of this magnitude, rare to say the least.

President Trump tweeting, now experts

are calling #Harvey a once in 500 year flood!

We have an all out effort going on and going well.

First responders and good Samaritans

are working around the clock trying to keep up

with all of the cries for help.

Those rescued, often left with nothing.

It's, like, memories that get, like,

taken away by, like, something that you don't expect,

but, I mean, it's all just materialistic stuff.

JENNA BROWDER: President Trump monitored the situation

from Camp David over the weekend.

He says he's ready to travel to Texas as soon as he can,

without causing disruption.

The White House says the trip will happen on Tuesday.

Jenna Browder, CBN News.