GALVESTON, Texas - As Hurricane Harvey gains strength, residents along the Texas coast aren't taking any chances; they're filling sandbags, stocking up on water and boarding up windows.
In Corpus Christi, where Harvey will likely make landfall and Mayor Joe McComb has issued a voluntary evacuation order, Walmart shelves were clearing quickly, as the city canceled Friday's dockets in city court and provided self-serve sandbags to residents.
Port Aransas on Mustang Island and nearby Portland issued mandatory evacuation orders. Houston, meanwhile, has canceled the first day of school on Monday.
Harvey is rapidly strengthening and is forecast to become a Category 3 hurricane with winds of at least 111 mph by the time it hits the middle Texas coast late Friday or early Saturday, the hurricane center said Thursday. After hitting Corpus Christi, the storm is expected to stall over the state, forecasters say.
Hurricane-force winds are a concern as the storm builds strength in the Gulf of Mexico, and a potential deluge and subsequent flooding may be a big danger as well, according to meteorologists.
"Harvey is likely to bring multiple hazards, including heavy rainfall, storm surge and possible hurricane conditions to portions of the Texas coast beginning on Friday," the National Weather Service said.
<strong>Slow storm means more rain</strong>
At 2 p.m. ET, Harvey was a Category 1 hurricane with 85 mph winds. It was about 335 miles southeast of Corpus Christi, and was moving north-northwest at 10 mph.
It's expected to bring 12 to 20 inches of rain to the Texas coast, with isolated instances where rainfall totals could reach 30 inches, the weather service said.
Rainfall amounts increase exponentially when a storm moves at a slower speed, as Harvey has been doing. Earlier this week, the National Hurricane Center warned, "The system is likely to slow down once it reaches the coast, increasing the threat of a prolonged period of heavy rain and flooding across portions of Texas, southwest Louisiana, and northeastern Mexico into early next week."
Compounding potential problems is the tidal cycle. If peak storm surge arrives during high tide, parts of the coast could see 2 to 8 feet of flooding, with the potential of 6 to 12 feet between Padre Island National Seashore and Sargent, Texas.
While it has been nine years since Texas last saw a hurricane, the state is no stranger to devastating flooding from tropical systems. In 2001, Tropical Storm Allison was a multibillion-dollar disaster for the state, specifically Houston. Allison became nearly stationary for days, dropping more than 30 inches of rain across portions of the city.
A hurricane watch is in effect from north of Port Mansfield to the mouth of the Rio Grande, with a storm surge watch stretching north to High Island, on Galveston Bay.
Harvey could be the first hurricane to hit Texas since 2008 when Hurricane Ike smashed the coast near Galveston. The storm killed 21 people in Texas, Louisiana and Arkansas, and caused widespread destruction.
<strong>'It scares the hell out of people'</strong>
As Harvey churned toward Texas, Gov. Greg Abbott declared a state of disaster Wednesday in 30 counties along the Gulf of Mexico. The governor's action allows agencies to "quickly deploy resources for the emergency response."
"Texans believe in taking action and always being prepared in the event of an emergency," Abbott said. "That is why I am taking every precaution prior to ... Harvey making landfall."
Students and staff at the Texas A&M campus at Corpus Christi are under a mandatory evacuation order. The campus will be closed starting Thursday, according to the university's website.
People around Corpus Christi started stocking up Wednesday on food, bottled water and other essentials.
"We know that if anything as far as flooding happens, that's the one thing everyone runs to, we have to have water," Mariah Barter told CNN affiliate KZTV. "It's a big deal. It scares the hell out of people. It's better to be prepared."
Others in South Texas readied sandbags, fueled up power generators and bought plywood to board up their windows, CNN affiliate KRIS reported.
At a Thursday afternoon White House briefing, Press Secretary Sarah Huckabee Sanders said President Donald Trump has been briefed on Harvey. She downplayed concerns about preparedness, given that there is no permanent Homeland Security secretary, and said the White House is in "great shape," given that chief of staff John Kelly was previously in charge of the office.
Concerns about high winds and higher tides have officials in Galveston making preparations ahead of Tropical Storm Harvey.
So far, no evacuations have been issued for residents on the island, but officials are telling people in low lying areas they may want to leave.
Video in to the ABC13 newsroom shows workers removing the lifeguard stations that are so familiar along the beaches on Seawall Boulevard.
Galveston prepares for potential for devastating floods
The work began around 3 a.m., and they are still out there working their way down the beach.
A bulldozer is being used to help move the stands. Slowly but surely, these workers will get them off the beach and out of harm's way.
Hotels and businesses on the Strand have sandbags piled high, in hopes of avoiding damage from potential floodwaters.
Several historical sites in Galveston have announced they will be closed from Friday until Sunday, including Bishop's Palace, the Tall Ship Elissa, and Pier 21 Theater.
Copyright 2017 Cable News Network. Turner Broadcasting System, Inc. All Rights Reserved.