(CNN) Workers at the Texas health care system's emergency operations center are keeping a close eye on the hospitals and nursing homes in the Port Arthur-Beaumont area closely Wednesday, hoping the flooding from Hurricane Harvey spares their medical facilities. But not all facilities have been so fortunate.

Patients at the Lake Arthur Place nursing home and rehabilitation facility in Port Arthur were evacuated Wednesday as hallways flooded. Some elderly residents sat in the water for up to 24 hours, CNN affiliate KTRK reported.

The Coast Guard and volunteer rescue workers moved frail and elderly patients who could not leave their wheelchairs -- or, in some cases, beds -- which had to be carried to waiting boats. Some patients' relatives came with their own boats. Describing it as a "very difficult situation," staff members vowed to stay until every single person was evacuated.

"All residents have been safely evacuated to either St. Elizabeth hospital or Baptist hospital in Beaumont," said a statment from Michelle Metzger, communications director for Senior Care Centers, which operates the facility.

Another one of their facilities, Cypress Glen, in Port Arthur, was also evacuated with the aid of boats transporting residents to a staging area.

"We currently are working with the Texas Office of Emergency Management to move all residents to another nursing center, and we are communicating these details to the families as quickly as we can. Our patients and residents are our highest priority," Metzger said.

At least 16 hospitals in Texas are closed due to flooding as of Wednesday, according to the Texas Department of State Health Services . Outpatient services, surgeries and pharmacies have been closed throughout the state, but ride-out crews at other facilities have worked through the storm to keep patients safe, even while some of their own families were in danger.

Nearly 1,000 patients have been moved from medical facilities throughout the state on 140 emergency missions. That means a complicated logistical operation that has been "anything but simple," said Chris Van Deusen, the health services department's director of media relations. But having seen its share of hurricanes, floods and wildfires over the years, Texas has "fortunately -- or unfortunately, depending on how you see it -- we all have a lot of practice at this," Van Deusen said.

has been coordinating with EMS assets including ambulances, ambulance buses, helicopters and boats to transfer patients out of harm's way. And if hospitals in any affected area run out of room, Van Deusen said, there are about 2,000 available beds across Austin and Dallas. The state's emergency medical task force has been coordinating with EMS assets including ambulances, ambulance buses, helicopters and boats to transfer patients out of harm's way. And if hospitals in any affected area run out of room, Van Deusen said, there are about 2,000 available beds across Austin and Dallas.

"The challenge early on was getting to the patients to transport them to additional medical centers," Van Deusen said. "The hospitals themselves in the impacted areas have had to become fairly self-contained, becoming pretty much an island, and it is difficult to get food and supplies in. Next, we'll all be coordinating volunteers and donated supplies. But we'll have to get through the flooding first."

St. Joseph set up a triage center in the hospital loading dock to care for the influx of patients.

One of the hospitals that has become self-contained is St. Joseph's Medical Center in downtown Houston, which has remained open for the duration of the storm. Staffers are delivering babies, handling emergencies and taking care of a number of evacuees from the nearby convention center. Unable to get back to their own homes due to impassable roads, employees have had to sleep at the hospital, but hospital leaders said they still volunteer to work extra hours.

St. Joseph's was prepared for the storm, and its floodgates held, but it's had to improvise on occasion. It created a triage center in an hour and 20 minutes, officials said, setting it up on a loading dock to handle an additional influx of patients quickly.

Though officials had ordered enough food and supplies, items like linens were running low when staffers had to sleep on the property. When the manager of an Embassy Suites hotel a few blocks away learned about the situation, he donated his extra linens to the hospital.

"We got one of our trucks and a van and set up a daisy chain to bring in 4,000 sets of sheets," said Bo Beaudry, the hospital's interim CEO. "We've been able to give some of those blankets away to people who came to triage wet and cold and even plugged a few leaks here and there. It's been a real test of people's resilience, and people keep coming through."

Another Houston hospital, Ben Taub, needed to transfer some patients who were more seriously ill after its basement flooded and a sewage pipe burst, shutting down parts of the kitchen. Rescue workers had to abort an evacuation attempt Sunday when the rain got too intense. But things got a little better when the sun broke through the clouds Tuesday afternoon.

"I think we've turned the corner," Ben Taub spokesman Bryan McLeod said Wednesday. The facility has restored its kitchen and had another delivery of food, which had been running low. Monday night, workers were also able to transfer three of the five patients they had been trying to evacuate.

"Three of them made it to their destination, but two had to come back due to high water, and that isn't something that should happen," McLeod said.

As a Level 1 trauma center, a hospital staffed and equipped to take in the most serious patients, Ben Taub is usually the facility that gets the transfers, he said, "not the other way around." But conditions in the area have improved enough that patients who had been stuck at the hospital since Friday were able to go home if they were well enough. With 345 patients at the beginning of the storm, Ben Taub was down to 307 by Tuesday night.

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"That was important so we can maintain the proper staff level and so that we can again start accepting patients who will need us," McLeod said.

When the floodwaters finally recede and things get a little closer to normal, hospital officials plan to send home staff and bring in fresh crews.

At St. Joseph's, Beaudry tells of being on a leadership call with the company's other hospitals about the need for relief staff. He put one of the hospital's managers on the phone to share his story about using a fire ax to break through his roof to be rescued from his flooded home. "There wasn't a dry eye," he said. And many volunteers said they would come down and help.