NEW YORK — A 77-year-old grandfather who slipped on wet stairs inside his beachfront housing complex became the 43rd New York City resident to die as a result of Superstorm Sandy, whose effects continued to be felt across the region Monday as basic services and public transportation crept toward normalcy.

More than 1,800 city residents remained in shelters, unable to return to homes damaged by the storm or still without heat and electricity. But for the first time since Sandy made landfall on Oct. 29, the number of households without power in affected states dropped below 100,000. As of Monday morning, the Department of Energy said 88,882 customers in New Jersey, New York, and West Virginia remained in the dark. New York was the worst affected, with 79,744 outages reported.

Officials of the Long Island Power Authority said they expected that 99 percent of their customers would have power back by the end of the day Tuesday.

In another post-Sandy first, officials Monday reopened to limited traffic the Gov. Hugh L. Carey Tunnel — formerly known as the Brooklyn-Battery Tunnel — a major artery under the East River connecting Manhattan to Brooklyn. Workers will continue trying to repair damage from 43 million gallons of salt water that poured into the country’s longest under-river vehicle passage.

“It was filled floor to ceiling for more than a mile with water and debris,” said the chairman of the city’s Metropolitan Transit Authority, Joseph Lhota. “No one has ever faced a challenge like this.”

Limited train service resumed linking Manhattan with New Jersey and Long Island. In New Jersey, gas rationing that had been in effect for more than a week was to be lifted Tuesday.

The latest storm victim, Albert McSwain, lived in a housing project in the Rockaways that was among those left without power. According to his daughter, Allison Lockett, who lived with him, the two went out for a walk on Oct. 31. When they returned to the building, its stairway dark and wet, Lockett told her father to wait while she ran upstairs to get a flashlight to guide them to their apartment.

Before she could return, he had slipped. Neighbors found him with wounds to his head and his body, paralyzed from the neck down. McSwain, a retired custodian at the New York Police Department Academy, died of his injuries at a hospital Saturday.

In announcing McSwain’s death, police also released a detailed accounting of some of the rescues that took place at the height of the storm, as electrical transformers exploded and dumped live wires into fast-rising water.

“Boats with and without powerful motors became useless and ineffective after some time due to the large debris, the strong current and depth of the water, and the small streets that were difficult to navigate,” said Sgt. Anthony Lisi of the police department’s Emergency Services Squad 5, which includes Staten Island. On Staten Island alone, more than 1,100 water rescues took place during and immediately after Sandy. The borough suffered the most casualties of any in the city, losing 23 residents.

“Additionally, live power lines were falling down into the water, making rescues extremely hazardous to first responders,” Lisi said.

Conditions worsened and each time a rescue boat arrived to fetch someone who had called 911 for help, “another 10 families on the block who needed to be evacuated would ask for assistance as well,” Lisi said.