A dangerous combination of storm surge and heavy rainfall has unleashed flooding in the greater Houston area on Tuesday as Beta, now weakened to a tropical depression, crawls along the Texas coast after making landfall.

The National Weather Service (NWS) forecast office in Houston warned that "excessive rainfall" will impact the nation's fourth-largest city throughout the day, leading to flash flooding.

"It's moving very slowly, so even though its a weakening system the fact that it's not moving very quickly is going to bring all this Gulf moisture in towards Texas and Louisiana," Fox News Senior Meteorologist Janice Dean said on "Fox & Friends." "The flooding is going to be a big concern with this system."

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Houston Police Chief Art Acevedo said Tuesday morning that "lots of street flooding" was reported across the city and urged people to not go out unless they need to.

Water rises from the storm surge of Tropical Storm Beta in The Strand as the storm moves toward landfall late Monday, Sept. 21, 2020, in Galveston, Texas. (Brett Coomer/Houston Chronicle via AP)

"Do not cross flooded roadways or go around barricades," he tweeted. "Turn around, don’t drown isn’t a slogan, it is a strategy to stay safe and alive."

Several freeways were also closed in the Houston area due to flooding, with drivers also being rescued.

School districts throughout the region were also shifting to remote learning for the day due to ongoing street flooding.

Beta made landfall Monday night near Port O’Connor, Texas, and is slowly moving northeast at 2 mph with winds of 35 mph, according to the National Hurricane Center (NHC).

Waves crash against the pier at Kingfisher Park in Port O'Connor, Texas, as Tropical Storm Beta moved into the area Monday, Sept. 21, 2020. (Emree Weaver/The Victoria Advocate via AP)

Forecasters said Beta is expected to stall inland over Texas on Tuesday by bringing more heavy rainfall inland and a lingering threat of dangerous storm surge and tide along the coast.

A man walks through a street flooded by Tropical Storm Beta Monday, Sept. 21, 2020, in Galveston, Texas. (Brett Coomer/Houston Chronicle via AP)

“We currently have both storm surge and rainfall going on right now,” NWS meteorologist Amaryllis Cotto in Galveston told the Associated Press.

TROPICAL STORM BETA MAKES LANDFALL ON TEXAS COAST

In Brazoria County storm surge was impacting the coastal town of Surfside, causing many to seek higher ground.

Jeff Williams gets back in his vehicle to try to get it out of the flooded road Monday, Sept. 21, 2020, in Surfside, Texas. (Godofredo A. Vásquez/Houston Chronicle via AP)

"We are on a bit of a hill here but the water was up on the road," Douglas Fees, manager of the Anchor Motel, told FOX26. "It's flooded in our RV park over there but trailers are gone right now. The dunes down there also took a big hit as well."

Adam Maubach, left, and Jo Dove look at the erosion caused by Tropical Storm Beta on Monday, Sept. 21, 2020, in Surfside, Texas. (Godofredo A. Vásquez/Houston Chronicle via AP)

Storm surge also flooded streets in Galveston.

Water rises from the storm surge of Tropical Storm Beta in The Strand as the storm moves toward landfall late Monday, Sept. 21, 2020, in Galveston, Texas. (Brett Coomer/Houston Chronicle via AP)

Up to 12 inches of rain has fallen in the area, with isolated amounts of up to 18 inches.

The threat of dangerous flash flooding is expected to continue through Wednesday, with isolated storm totals of up to 20 inches of rain expected along the middle and upper Texas coast.

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Beta was the ninth named storm that made landfall in the continental U.S. this year. That tied a record set in 1916, according to Colorado State University hurricane researcher Phil Klotzbach. It also was the first time a Greek letter-named storm made landfall in the continental U.S.

Beta will continue to weaken as it stalls across the coast, however, heavy rainfall will be a big risk for Southeast Texas into Louisiana and the Mississippi Valley over the next few days.

The forecast track of Tropical Storm Beta (Fox News)

Gov. Greg Abbott issued a disaster declaration on Monday for 29 Texas counties ahead of Beta’s arrival.

Flood advisories stretch from Texas into Louisiana as Tropical Storm Beta slowly moves along the coast. (Fox News)

The rainfall and storm surge also prompted Louisiana Gov. John Bel Edwards to declare a state of emergency.

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In Lake Charles, Mayor Nic Hunter told the AP he was worried Beta’s rainfall could set back efforts in his Louisiana community to recover after Laura, which damaged about 95% of the city’s 30,000 structures.

Expected rainfall amounts through Thursday from Tropical Storm Beta (Fox News)

Hunter said the worry of another storm was “an emotional and mental toll for a lot of our citizens.

The Associated Press contributed to this report.