More than 90,000 customers across Maine were still without power late Monday as repair crews from the state’s two major electric utilities continued to work around the clock to restore electricity to homes that lost it during Sunday’s snowstorm.

At 6:30 a.m. Tuesday, Central Maine Power Co. reported that 49,720 customers were still without power, and Emera Maine said it had 34,887 outages.

The snowstorm caused the most damage in the midcoast. There were 16,236 CMP customers without power in Knox County, 13,586 in Waldo County, 7,513 in Lincoln County, and 5,193 in Hancock County late Monday.

“The heavy snow and strong winds knocked out power to more than 80 percent of the homes and businesses in some counties along the midcoast,” CMP spokeswoman Gail Rice said in a news release. “The severity of the damage and icy roads are adding to the difficulties facing crews in those areas.”

Late Monday, Rice issued another statement saying that CMP expects to restore power to 90 percent of its customers by Wednesday evening.

Emera Maine, which serves northern and Down East Maine, brought in repair crews from New Brunswick and Nova Scotia to help repair what spokeswoman Susan Faloon described as “massive storm damage.”

“A helicopter patrol helped locate trees on transmission lines and numerous broken tree limbs and snapped utility poles were discovered as well,” Faloon said in a statement Monday. “Crews will continue to work through the night.”

Faloon said it might not be until the end of the day Thursday before some customers in Penobscot and Hancock counties have their power restored. Washington County customers were expected to have their power restored by Tuesday evening and northern Penobscot and Piscataquis counties by the end of Wednesday.

Thousands of CMP customers across central Maine were also without power Monday evening as the company raised concerns about the potential for relocating polling places if power is not restored by morning. Electricity was out to about 2,191 customers in Kennebec County and about 1,938 in Somerset County.

Late in the day Monday, Secretary of State Matt Dunlap encouraged people to plan to vote as usual in hopes that utility crews will restore power in time.

“As long as people can mark their ballots by 8 p.m. on Election Day, their vote will be counted,” he said. “Any adjustments that need to be made will be made public as broadly as we can.”

Towns forced to relocate their polling places will be listed online via a link at Maine.gov/sos;Maine.gov/sos. There also will be a sign on the door at the traditional polling places directing voters to an alternate location. Dunlap advised voters to check with their town or city clerk to see if their scheduled polling place will remain open.

CMP said its crews are scrambling to restore power as quickly as possible.

“Our focus today is to restore service on some of our major lines as we bring in additional crews and assess the damage on our system,” Rice said Monday. “We also have people in helicopters surveying transmission lines from the air to make sure we have a complete assessment of the damage to our system.”

State officials have responded to the outages by opening warming shelters throughout Penobscot, Waldo and Knox counties, including in Washington at Gibbs Library on Old Union Road.

State offices in Ellsworth, Rockland and West Boothbay were closed Monday due to the continued impact of the storm.

Several inches of heavy, wet snow blanketed much of the state, causing hundreds of accidents. Winds that gusted to more than 40 mph brought down trees and limbs, adding to the challenge.

The Maine Center for Disease Control and Prevention issued a warning to residents without power to be wary of carbon monoxide poisoning that could be caused by gas-powered generators, kerosene heaters or other power sources. Generators must be placed outdoors at least 15 feet from windows or doors, according to the CDC. Kerosene heaters should be used in well-ventilated rooms.

Rice warned against using nontraditional sources of heat, such as grills or camp stoves. She also urged homeowners who wish to install a permanent generator to hire a licensed electrician. Portable generators must be properly grounded, Rice said.

She also stressed continued caution around downed lines.

“Everyone should stay clear of any downed power lines or fallen trees that may be tangled in the lines,” Rice said. “All downed lines should be considered live and dangerous. Customers should leave the cleanup to our crews, who are trained and equipped to handle these situations safely.”

In Somerset County, dispatchers took 92 complaints of trees and wires down Sunday and 80 reports of motor vehicle accidents, according to Emergency Management Director Michael Smith.

“We’re definitely lucky compared to some of the coastal communities. They really got hit,” Smith said.

“It was an extremely busy day,” Smith said. “The first snowstorm of the year, people always forget that they’re driving on snow and ice now, and it tends to be the storm that really hits us in dispatch.”

The storm’s effects were mostly felt in the eastern part of the state, with the highest snowfall accumulation in the Penobscot County town of Orrington, where the National Weather Service reported 17 inches of snow.

“To get that much snow this early in the year, it doesn’t happen,” said Michael Cempa, a meteorologist for the weather service in Gray. “We’re used to getting a little bit of snow, but not that much this soon.”

Augusta and Waterville appeared to have received a couple of inches of snow, but exact totals for the two cities were not available from the weather service, which collects data on snowfall from volunteers around the state, Cempa said.

In Kennebec County, 5.5 inches were reported in Vassalboro and 4 inches in Winslow.

In Somerset County, 6 inches were reported in Harmony.

In Waldo County, 12 inches were reported in Prospect, 11 inches in Winterport and 10 inches in Belfast, he said.

The highest wind gusts in the state were reported in Augusta, which recorded 50-mph gusts.

“It’s one storm that happened to work out that way and everything came together to produce that snow. I don’t think it necessarily says anything about the winter ahead,” Cempa said.

Temperatures are expected to warm up for the rest of the week, with highs in the upper 40s to around 50 degrees. The next chance of any precipitation is Thursday and is expected to be rain, he said.