Harvey: Before and after photos show extent of destruction

The city has been hit with 25 inches of rain so far

Houston's market Street is shown before and during tropical storm Harvey's floods (YouTube/New York Times)

Images from before and after Harvey show the striking effect the tropical storm has had on Houston, Texas.

One photo shows an entire highway underpass flooded with rainwater. Another highway has been fully submerged, all the way up to its street signs. In nearby Rockport, Texas, video shows homes demolished by the storm’s rain and winds.

“It's like something from a movie,” one commenter wrote after seeing the pictures. “My brain is having real difficulty taking this in as real.”

Harvey hit the eastern coast of Texas as a category-four hurricane on Friday, before travelling to Houston, where it was downgraded to a tropical storm.

Despite the official downgrade, Harvey’s rains have wreaked havoc on the city, covering it in 25 inches of rain in just two days. According to the National Weather Service, some areas could see 50 inches of water before the storm ends.

Officials say 5,000 people have fled to local shelters, and experts estimate more than 30,000 could be displaced before the storm is over. Police had completed more than 2,000 rescues by Monday. Experts say recovery could take years.

President Donald Trump has issued a state of emergency in both Texas and Louisiana. He is expected to visit Texas on Tuesday.

Meanwhile, flooding is only expected to increase, as Houston officials release water from the city's reservoirs in an attempt to relieve pressure from the rain.

“If we don’t begin releasing now, the volume of uncontrolled water around the dams will be higher and have a greater impact on the surrounding communities,” said Col. Lars Zetterstrom, Galveston District commander of the Army Corps of Engineers.