'Unprecedented' Rainfall and 'Catastrophic' Flooding Devastate the Gulf Coast

With at least five reported dead after Hurricane Harvey slammed into the Gulf Coast earlier this weekend, Texas residents are expected to continue battling "unprecedented" rainfall and life-threatening, "catastrophic" flooding for several days.

"An extremely serious situation with few if any close parallels in modern U.S. hurricane history is taking shape over the southeast third of Texas."
--Jeff Masters, Weather Underground

Although what was a category 4 hurricane on Friday is now considered a tropical storm, the forecast has alarmed weather experts, who are warning residents of Louisiana and Texas--particularly those in the Houston metro area--to prepare for more intense floods and, if possible, avoid traveling in affected areas.

"An extremely serious situation with few if any close parallels in modern U.S. hurricane history is taking shape over the southeast third of Texas," writes meteorologist Jeff Masters for Weather Underground.

"There is very little doubt that Texas is in for one of the worst rainfall and flood events in its history," Masters writes. "The resulting rainfall is very likely to produce widespread, devastating, and potentially catastrophic flooding. The situation in Houston is particularly concerning, given that city's vast size and population and its well-known vulnerability to flooding."

William "Brock" Long, director of the Federal Emergency Management Agency (FEMA) echoed Masters' concerns on Sunday, when he told the Washington Post: "This will be a devastating disaster, probably the worst disaster the state's seen."

The National Weather Service predicts that in the next 24 hours alone, at least five Texas counties will experience more than 20 inches of rainfall.

Rising floodwaters in and around Houston on Saturday forced many residents who had not already fled the storm to climb to their attics and rooftops, and anxiously await the overwhelmed emergency response crews.

"A fleet of helicopters, airboats, and high-water vehicles confronted flooding so widespread that authorities had trouble pinpointing the worst areas," the AP reports." Rescuers got too many calls to respond to each one and had to prioritize life-and-death situations."

In Harris County--which includes Houston and is the nation's fourth most-populous county--emergency crews have performed 1,500 to 2,000 high-water rescues since Saturday night, the Houston Chronicle reports, but "the county is operating at full capacity and doesn't have enough boats and high-water vehicles to meet the region's needs."

"We asked the state for additional resources, but they can't get here," Harris County Judge Ed Emmett told the Chronicle. "We had everyone in place," he said, but "this is unprecedented." Emmett has asked residents with high-water vehicles and boats to assist with rescue efforts, which continued across the region on Sunday, despite road closures and other obstacles.

I-45, "the major interstate from Galveston through Houston, is shut down in places because of high water," CNN reports, and one of Houston's largest public hospitals was forced to evacuate on Sunday because rising water endangered its electrical system.

In additional to local and state emergency responders, FEMA's director, Long, said there are already 5,000 federal employees in Texas to respond to the crisis. Along with his controversial Friday night news dump as the hurricane barreled toward Texas, President Donald Trump approved a disaster declaration for the state, enabling FEMA to provide assistance.

"The recovery to this event is going to last many years, to be able to help Texas and the people impacted by this event achieve a new normal," Long told the Post.

Although it's too early to measure the damage--with so much more flooding anticipated--as the storm approached on Friday, many worried about the oil and gas facilities located along the Texas Gulf Coast. AP reports that on Friday, "at least three refineries had closed and at least two petrochemical plants had suspended operations," and on Sunday, ExxonMobil announced it was shutting down the second-largest refinery in the country. In addition to the economic impact, there are major concerns that the flooding will create a "nightmare situation" for the environment.

Journalists and residents who remained in the flooded regions this weekend shared startling images of the rising waters and rescue efforts:

Daybreak in Houston.... so many water rescues that the US Coast Guard & Texas National Guard assisting. pic.twitter.com/htn9pCMHLn

-- Dax Clark (@TheDopplerDax) August 27, 2017

This story has been updated.