Tina Abbott had already been struggling to stay on top of her medical issues. There was the pain from a tear in her arm tissue, the cyst on her spine and the chronic breathing problems that required a portable oxygen tank, which she had refinanced her car to afford.

Then Hurricane Helene hit western North Carolina, forcing her to cancel an appointment for lab work. When a trio of volunteer doctors arrived at her home days later, Ms. Abbott, 67, was sitting in her dark living room, without reliable cell service or running water.

With the region essentially shut down, she was worried about how she would get oxygen refills and blood tests to monitor the impact of her many medications on her organs.

“If this goes on forever,” she told the volunteer doctors, “it’s going to be a problem.”

Even before the storm sent floodwaters raging through this slice of mountainous Appalachia, the largely rural region had a lot of people in poor health, with medical care often challenging to get. And while North Carolina’s recent expansion of Medicaid has allowed many more residents with limited income to get health coverage, the hurricane’s devastation is hindering that progress, at least for now.

The storm is among the deadliest in the nation’s history. After making landfall in Florida’s Gulf Coast in late September, Helene tore through the Southeast, killing more than 200 people and decimating hundreds of homes and businesses. The devastation is particularly acute in western North Carolina, where floodwaters swept away entire communities and destroyed much of its mountainous infrastructure.