Houston Deluge Kills At Least 5 As Disastrous Flooding Likely to Continue

A wave of disastrous flooding has left America's fourth largest City under 20 inches of water in some places.

At least five have been killed in Houston and hundreds rescued as a wave of soaking rains has left parts of the city of two million drowned in 20 inches of floodwater.

And more flooding is likely.

According to Weather.com, rainfall fell at rates as high as four inches an hour. As waterways in Houston, which sits just a few feet above sea level, rapidly flooded on Monday, residents found themselves trapped in their own homes and vehicles.

Read: Camera Rolls as TV Reporter Helps Motorist Swept Away in Texas Floodwaters

On Tuesday, more flash flooding was possible as thunderstorms continued to relentlessly sweep the soaked region. The National Weather Service had the area under a flash flood watch through Wednesday morning.

Texas Gov. Greg Abbott declared a state of disaster in nine counties in and around the Houston area.

 Watch: This $200,000 Lamborghini Drives Through Flood Waters Like a Boss

In addition to the people who have been affected by the historic flooding, more than 70 horses had to be rescued in North Houston when waters rose too quickly for their owner to evacuate them.

According to KTRK, several horses were seen on video Monday morning struggling to keep their heads above rising flood waters.

Rescuers said their main concern was to save trapped people, however Houston SPCA rescuers were called in to help the horses. None of the animals died, according officials.

Watch: These Three Steps Could Save Your Life if You're Caught in Your Car in a Flood