PORTLAND, Maine — Utility crews reinforced with out-of-state line workers had restored electricity Tuesday to about 70,000 homes and businesses left in the dark by a wind-whipped storm that dumped 2 feet of snow in parts of Maine.

More than 140,000 customers were without power at the peak of Monday’s storm as wet, heavy snow snapped tree limbs, power lines and utility poles. By Tuesday morning, utility crews had restored electricity to roughly half of those customers.

Central Maine Power Co. had 65,000 customers without power and planned to reduce that number to 30,000 by Tuesday night, CMP spokesman John Carroll said. All customers should have their electricity restored by Thursday night, Carroll said.

About 5,700 Bangor Hydro Electric Co. customers were still without power Tuesday morning. The company said some homes in outlying areas of the state could be without electricity into Wednesday.

The utilities said poor road conditions and the rural locations of many outages slowed efforts to restore power.

“The roads are narrow because snowbanks are so big and high, so once the crews get off the road they’re having a hard time getting around,” Carroll said.

Fifteen shelters were set up around the state Monday night, but only a small number of people spent the night there.

“That’s typical,” said Lynette Miller of the Maine Emergency Management Agency. “We need to have the shelters available, but people tend to tough it out or go to family or friends.”

Gov. John Balducci declared a state of emergency Monday to extend the hours that power crews can work to restore electricity. On Tuesday morning, he joined CMP President Sara Burns in touring neighborhoods in Brunswick and Bath that remained without power.