As overnight temperatures fell to the 40s, power crews in more than a dozen states navigated a tangle of fallen trees, downed power lines and dangerous floodwaters in the painstaking, house-by-house work of reconnecting millions of customers left in the dark by Sandy.

Power was restored by late Thursday to about half of 10 million households and businesses that lost electricity during the storm, according to the Edison Electric Institute, a trade group that represents investor-owned utilities. But millions more remained cut off from power needed to operate furnaces, heaters, refrigerators and lights.

"It's freezing like an ice box," said Lydia Crespo, who was using a gas stove to heat her home in Staten Island, N.Y., still without power. "No hot water, no light. All you smell is the gas, the oil, the mold."

The death toll attributed to Sandy reached at least 90, authorities said Thursday. Transit bottlenecks began to ease in New York City with the reopening of some subways, but in New Jersey and elsewhere lines stretched long from gas stations lucky enough to have both electricity and gasoline. Amtrak said it would resume southbound train service from Pennsylvania Station on Thursday evening, and limited service to Boston on Friday. Late on Thursday NJ Transit announced that limited service into New York's Penn Station would begin Friday, but the system remained largely out of service.

U.S. Air Force cargo planes were flying utility crews and 636 tons of equipment, including electric company bucket trucks, to speed power restoration.