It was predicted that downtown Houston would be submerged under ten feet of water. Compulsory evacuations, then, were ordered on August 27. The expectation was that within two days the area would become impassable due to the overwhelming volume of rain and floodwater Harvey brought with it.
Although attempts were made by the U.S. Army Corps to disperse the build-up of floodwater, it was for some part in vain. According to one estimate, around a quarter of Harris County – an area that includes Houston and some 4.5 million people call home – was submerged. The flooded area totalled 444 square miles.