29/08/2017 13:57 SAST | Updated 29/08/2017 13:57 SAST

Here's What You Need To Know About Hurricane Harvey

Rain from the worst storm to hit the Houston region in 50 years pummelled the area again on Monday as rescue efforts continued. With water levels rising and rain from Tropical Storm Harvey predicted to continue through Thursday, officials warned of a long and difficult recovery for residents of the country's fourth-largest city.

"We've got to recognize a new normal, a new and different normal for this entire region," Gov. Greg Abbott (R) said Monday.

Here's what you should know about the ongoing impact of the storm.

Scott Olson via Getty Images
People make their way out of a flooded neighborhood after it was inundated with rain water, remnants of Hurricane Harvey, on August 28, 2017 in Houston, Texas.

It's already one of the worst flooding disasters in recent U.S. history.

Since the storm made landfall on Friday evening, more than 30 inches of rain have fallen in parts of Texas, in some cases nearly doubling previous records. So much rain has drenched the state that the National Weather Service added a new color to its maps to illustrate the intensity.

The storm has flooded highways and streets, destroyed buildings, and displaced thousands of people from their homes. As of Monday evening, more than 100,000 people in the Houston area were without power.

Brock Long, of the Federal Emergency Management Agency, predicted Sunday that it will take years for Texas to recover from the damage. The agency expects more than 450,000 people will seek federal assistance for storm recovery, and anticipates at least 30,000 people will be displaced.

"This disaster is going to be a landmark event," Long told CNN.

Property damage alone is expected be in the tens of billions of dollars, according to an Associated Press report. Other major economic effects will include oil refinery shutdowns, and the closure of shipping ports and airports, including Houston's George Bush Intercontinental Airport.

The state also was threatened by toxic pollution from damaged refineries and chemical plants. Some residents of nearby communities have reported powerful odors. Authorities on Monday issued a chemical leak warning in La Porte and Shoreacres.

At least 10 people have died in the storm.

Over the weekend, at least two people were killed in storm conditions. On Monday, police confirmed the deaths of six people in Harris County. A woman in Montgomery County was also killed when a tree fell on her home.

On Monday night, Precinct 3 of the Montgomery County Constable's Office said a man in his 60s was presumed dead after he attempted to swim across "exceptionally fast moving" flood waters.

More deaths are likely to be reported in coming days as responders have thus far focused efforts on rescuing people in life-threatening situations.

Bloomberg via Getty Images
Houses and vehicles at the Highland Glen subdivision stand in floodwaters due to Hurricane Harvey in Spring, Texas, U.S., on Monday, Aug. 28, 2017.

More rain is on the way.

Heavy rainfall is predicted to continue throughout the week, and some areas may receive as much as 50 inches. (For some perspective, Houston on average receives roughly 49 inches of rain annually.) Torrential rains were also expected to reach parts of Louisiana, increasing fears of flooding there.

"I want to stress that we are not out of the woods yet," Elaine Duke, acting Department of Homeland Security secretary, said. "Harvey is still a dangerous and historic storm."

Officials urged residents against traveling to affected areas and told them to stay off the roads as the storm continues.

As a preventative measure, the Army Corps of Engineers began a controlled release of water from two giant flood-control dams in Houston early Monday morning, sending even more water into the city and potentially impacting thousands of residents. The Addicks and Barker dams, which have been described as "extremely high risk" during times of flooding, hold a combined 410,000 acre-feet of water. If the dams should fail, half of Houston could find itself underwater.

Despite the controlled releases, the water levels from both dams reached record highs on Monday. Officials warned that uncontrolled releases from the dams are possible Tuesday if water levels continue to increase. (Here is a list of neighborhoods that could be impacted by releases from the dams.)

Thousands of people have been rescued, and major relief efforts are underway.

Mandatory evacuations were issued in parts of several Houston-area counties, while other areas were under voluntary evacuation advisories. You can see a full list of evacuations here.

More than 3,000 people have been rescued from flooded buildings and cars. Francisco Sanchez, of Harris County's Office of Homeland Security and Emergency Management, told HuffPost that most people in life-threatening situations have been rescued.

When Harris County became swamped by calls from residents in distress over the weekend, county judge Ed Emmett asked people with boats to aid in rescuing residents who were trapped in their homes.

"We are asking the public to help," Emmett said. "We need you to help."

The Harris County Sheriff's Office said Monday night that it was no longer looking for volunteers with boats and high water vehicles. However, help from the public was still needed.

Medical centers were forced to take major precautions as water levels rose. Several hospitals deployed emergency flood doors intended to seal lower levels and protect patients and equipment. Ben Taub Hospital in Houston evacuated some patients, as did a Houston-area location of St. Luke's Hospital.

Aid organizations, such as the American Red Cross, opened shelters in the Houston area to house those displaced by the storm. One of those shelters — set up inside the George R. Brown Convention Center in downtown Houston — saw an influx of about 9,000 people since Saturday, reported KHOU-TV. The estimated capacity of the convention center was 5,000. A Red Cross spokesperson told AP that aid workers were trying to make more space inside the building, but a lack of cots meant many evacuees would have to sleep on the floor or on chairs.

Dallas' main convention center was also preparing to become a "mega-shelter" that could host 5,000 evacuees. Dallas Mayor Mike Rawlings said on Monday that the city had been told to prepare for tens of thousands of evacuees.

Go here for more information on how to aid relief efforts.

Erich Schlegel via Getty Images
Local apartment residents cross high water on North Braeswood Blvd to escape the flooding from Hurricane Harvey August 28, 2017 in Houston, Texas. 

Federal and state governments are activating emergency resources.

President Donald Trump declared a state of emergency in both Texas and Louisiana, allowing state officials access federal disaster resources. The president also said he believes Congress will pass a multi-billion dollar aid package "very quickly."

Abbott, meanwhile, activated the state's entire National Guard, dispatching roughly 12,000 soldiers to help with relief efforts.

"It is imperative that we do everything possible to protect the lives and safety of people across the state of Texas as we continue to face the aftermath of this storm," the governor said Monday. "The Texas National Guard is working closely with FEMA and federal troops to respond urgently to the growing needs of Texans who have fallen victim to Hurricane Harvey, and the activation of the entire Guard will assist in the efforts already underway."

The state is also setting up food and water distribution centers in affected areas.

Trump will visit Texas on Tuesday.

The president and first lady Melania Trump will travel to Corpus Christi, Texas, to visit areas impacted by the storm.

"I'll be going to Texas tomorrow, I look very much forward to it," Trump said on Monday. "Things are being handled really well. The spirit is incredible of the people."