CBS News August 25, 2017, 7:10 AM

Forecasters say Houston, America's fourth-largest city, could get at least 20 inches of rain as Hurricane Harvey bears down on Texas. Houston is also a major port, and the home of a multi-billion dollar petrochemical industry.

As Houston starts to feel the first effects of Hurricane Harvey, the comparisons to Hurricane Ike in 2008 have already begun. Scientists say that if Harvey stays on track it could cause destruction on a far greater scale, reports CBS News' Manuel Bojorquez.

With Harvey's arrival now imminent, people are moving inland, away from the low-lying coastal areas that were nearly obliterated by Ike in 2008.

Hurricane Ike holds the distinction of being the costliest weather event in Texas history: 103 people were killed in the U.S. while about $30 billion was spent to repair the damage

The Galveston sea wall is 17 feet high. A storm surge over that could travel from the Gulf of Mexico, into Galveston Bay, and up the Houston shipping channel, crippling one of the nation's busiest ports. It's also home to several major refineries.

"Hopefully this is a wake up call but this could become an absolute horror," said Jim Blackburn, an environmental engineer at Rice University. "If we reach those levels, we could see the worst environmental disaster in United States history. And we'd probably shut down and cause a major gap in gasoline and jet fuel and other types of critical products' availability."

For some Texans, that's reason enough to leave town.

"We don't know what's going to happen. We don't know if we're gonna come back to a home or what damage we're coming home to. So it's kind of sad. It's scary," said one woman preparing for the storm.

The Houston international shipping channel is the lifeblood of the nation's petrochemical industry. And with Hurricane Harvey on course to hit a cluster of refineries that outputs five million barrels of oil a day, gas prices have already surged – reaching their highest level in the past three months.

https://www.cbsnews.com/news/hurricane-harvey-poised-to-slam-major-houston-port/