Rescuers continued to fan out across the North Carolina mountains on Tuesday morning, scouring the region for missing people and rushing supplies to the many communities that were still in dire need of food, water and power after Hurricane Helene.

As of Monday evening, more than 120 people across six states had died as a result of the storm, which made landfall late last week, and the toll was expected to rise. Almost a third of those killed were in the county surrounding Asheville, N.C.

Throughout southern Appalachia, many of the roads that had until recently served as lifelines for small mountainside towns were flooded, destroyed or blocked by debris. In some areas of the Carolinas, power was still scarce after flooding from the storm submerged electrical substations.

And in communities all across the South, cellphone service — at precisely the time when it couldn’t be needed more — was spotty or nonexistent.

The scope of the damage left state and federal politicians reaching for superlatives on Monday. Gov. Brian Kemp of Georgia said that the storm was “unprecedented.” Gov. Roy Cooper of North Carolina described the destruction as “beyond belief.” Vice President Kamala Harris called the damage “heartbreaking,” and President Biden said the hurricane was “history-making.”

Mr. Biden promised long-term aid and said that he would visit North Carolina for a briefing and to survey the damage from the air on Wednesday. He also said that he planned to visit Florida and Georgia as soon as possible.