HARTFORD, Conn. >> Residents across the Northeast woke up to cold, dark homes and one of the earliest snow days in memory Monday after a storm dumped as much as 30 inches of wet, heavy snow that snapped trees and power lines and disrupted plans for Halloween trick-or-treating.

Communities from Maryland to Maine that suffered through a tough winter last year followed by a series of floods and storms went into now-familiar emergency mode as schools and roads closed, shelters opened, regional transit was suspended or delayed, and local leaders urged caution.

The storm’s lingering effects likely will outlast the snow. Temperatures are expected to begin rising Monday and the heavy, wet snow will start melting, the National Weather Service said.

The early nor’easter had utility companies struggling to restore electricity to more than 3 million homes and businesses. By early Monday, the number of customers without power was still above 2 million but falling. But officials in some states warned it could be days or even a week before residents have power again, even though crews have been brought in from as far away as Michigan and Canada.

"We are in full restoration mode," said Marcy Reed, president of National Grid Massachusetts.

Trees, branches and power lines still littered roads and rail lines throughout the region, leading to a tough Monday morning commute for many. Motorists hunted for open gas stations as power failures rendered pumps inoperable.

At a 7-Eleven in Hartford, two dozen cars waited early Monday in a line that stretched into the street and disrupted traffic.

"There’s no gas anywhere," said Debra Palmisano, of Plainville, who spent most of the morning looking for gas around the capital city. "It’s like we’re in a war zone. It’s pretty scary, actually."

Some local officials canceled or postponed Halloween activities, fearful that young trick-or-treaters could wander into areas with downed power lines or trees ready to topple over.

"With so many wires down … the sidewalks will not be safe for pedestrians (Monday) night," Danbury Mayor Mark Boughton told The Hartford Courant.

A weekend that should have brought activity no more strenuous than raking colorful autumn leaves left Northeasterners weather-weary.

"You had this storm, you had Hurricane Irene, you had the flooding last spring and you had the nasty storms last winter," Tom Jacobsen said Sunday while getting coffee at a convenience store in Hamilton Township, N.J. "I’m starting to think we really ticked off Mother Nature somehow because we’ve been getting spanked by her for about a year now."

In New Jersey, Gov. Chris Christie declared the damage to utilities worse than that wrought by Irene, a deadly storm that blew through the state in August. Things were similar in Connecticut, where the power loss of 800,000 broke a record set by Irene. By early Monday, around 400,000 people lacked power in New Jersey and more than 750,000 in Connecticut.

The snowstorm smashed record snowfall totals for October and worsened as it moved north. Communities in western Massachusetts were among the hardest hit. Snowfall totals topped 27 inches in Plainfield, and nearby Windsor got 26 inches. The snowstorm was blamed for at least 12 deaths, and states of emergency were declared in Connecticut, Massachusetts, New Jersey and parts of New York.

"Look at this, look at all the damage," said Jennifer Burckson, 49, after she came outside Sunday morning in South Windsor to find a massive tree branch had smashed her car’s back windshield. Trees in the neighborhood snapped in half, with others weighed down so much that the leaves brushed the snow.

Compounding the storm’s impact were still-leafy trees, which gave the snow something to hang onto and that put tremendous weight on branches, said National Weather Service spokesman Chris Vaccaro. That led to limbs breaking off and contributed to the widespread power failures.

"This is not going to be a quick fix," said Peter Judge, a Massachusetts emergency management official.

Sharon Martovich of Southbury, Conn., who was grocery shopping Sunday morning in nearby Newtown at one of the few businesses open for miles, said she hoped the power would come back on in time for her husband’s Halloween tradition of playing "Young Frankenstein" on a giant screen in front of their house.

"We would be really sad and it would disappoint a lot of people if we can’t play ‘Young Frankenstein,’" she said. But no matter what, they will make sure the eight or so children who live in the neighborhood don’t miss out on trick-or-treating.

"Either way we will get the giant flashlights and we will go," she said.

She was already making the best of the power failure. After the lights went out around 4 p.m. Saturday, she invited neighbors over for an impromptu Halloween party with wine and quesadillas in front of her propane fireplace.

Around Newtown, snow-laden branches were snapping off trees every few minutes, and roads that were plowed became impassible because the trees were falling so fast.

Along the coast and in such cities as Boston, the relatively warm ocean helped keep snowfall totals much lower. Washington received a trace of snow, tying a 1925 record for the date. New York City’s Central Park set a record for both the date and for October with 1.3 inches.

But in New Hampshire’s capital of Concord, more than 22 inches fell, weeks ahead of the usual first measurable snowfall. West Milford, N.J., about 45 miles northwest of New York City, had 19 inches Sunday.

Rail service was getting back up to speed across the region, though delays were expected. Amtrak had suspended service on several routes, and one train from Chicago to Boston got stuck overnight in Palmer, Mass. The 48 passengers had food and heat, a spokeswoman said, and were taken by bus Sunday to their destinations.

North of New York City, dozens of motorists were rescued by state troopers after spending up to 10 hours stranded on snow-covered highways in Dutchess and Putnam counties.

Deaths blamed on the storm included an 84-year-old Pennsylvania man killed by a tree that fell on his home, a person who died in a traffic accident in Colchester, Conn., and a 20-year-old man who was electrocuted in Springfield, Mass.

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Contributing to this report were Associated Press writers Michael Melia in Hartford, Conn.; Noreen Gillespie in Newtown, Conn.; Mary Esch in Albany, N.Y.; Ron Todt in Philadelphia; David B. Caruso, Colleen Long and Deepti Hajela in New York; Holly Ramer in Concord, N.H.; and Bruce Shipkowski in Trenton, N.J.