VIDEO: Houston first responders work to rescue stranded residents
Flooding in some parts of the county that includes the city of Houston is so bad that residents are being urged to seek refuge on their roofs.
Harris County Flood Control District official Jeff Lindner says people inundated by rising waters shouldn't crawl into attics of their homes but should get on top of them.
He says rainfall of more than 4 inches per hour has sent water higher than in recent Houston floods side and are exceeding levels seen in Tropical Storm Allison in June 2001.
Lindner says areas south of the city appear hard-hit and some flooding is reported in downtown Houston and in the Texas Medical Center, which was devastated in Allison.
He calls Harvey "a different animal" from Allison and a "historic situation."
He says he's most amazed that he's getting reports "of water into second-story of apartments and homes." Considering Houston's flat terrain, "it's very rare to get that depth of water."