Updated

Thousands of schoolchildren around the Northeast had one of the earliest snow days in memory on Monday after a snowstorm dumped as much as 30 inches of wet, heavy snow that snapped power lines and trees, causing widespread power outages that threatened to disrupt Halloween trick-or-treating.

Communities from Maine to Maryland went into now-familiar emergency mode as shelters were opened, inaccessible roads were closed, 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 says.

The unseasonably early nor'easter had utility companies struggling to restore electricity to millions of homes and businesses. By late Sunday, the number of outages had dipped to below three million and continued falling. But Officials in some states warned that 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.

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," said Danbury Mayor Mark Boughton told The Hartford Courant. "We have 200 streets with wires down ... (we) would hate to have children hurt."

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."

The storm 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 11 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 were 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 outages.

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

The more than 800,000 who lost power in Connecticut broke a record for the state that was set when the remnants of Hurricane Irene hit the state in August, said Gov. Dannel P. Malloy.

This outage will be worse than the one caused by Irene, said Peter Bloom, 70, of South Windsor, because he relies on electricity to heat his home.

"I'm going to put another blanket on. What else can I do?" he said Sunday as he gassed up a snow blower to clear his driveway. "At least I'll save a few bucks on my electric bill."

The severity of the storm caught many by surprise, and it disrupted Halloween plans, too.

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's hoping the power will 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 outage. After her power went out at about 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. Roads that were plowed became impassible because the trees were falling so fast.

Along the coast and in such cities as Boston, relatively warm water temperatures 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 the month of October with 1.3 inches of snow.

But in New Hampshire's capital of Concord, more than 22 inches fell, weeks ahead of the usual first measurable snowfall. Trees downtown still bright with fall colors were covered with snow. Some didn't survive -- a large oak tree that had stood alongside the Statehouse fell, partially blocking a side street.

By 8 a.m., Dave Whitcher had already been clearing dozens of parking lots around town for eight hours as part of his work as a property manager.

Holding up his shovel, he said, "Me and this guy are going to get to know each other real well today."

Some other inland towns got more than a foot of snow. West Milford, N.J., about 45 miles northwest of New York City, saw 19 inches by early Sunday.

New Jersey's largest electric and gas utility, PSE&G, warned customers to prepare for "potentially lengthy outages" and advised power might not be fully restored until Wednesday. More than 612,000 lost electricity in the state, including Gov. Chris Christie.

Utility crews were out in force Sunday, but downed trees and messy roads were hampering their efforts.

They also delayed rescues of motorists stranded along highways in upstate New York, where 50 to 75 vehicles were towed overnight. A commuter train was also evacuated, and passengers were taken to a shelter, state troopers said.

Residents were urged to avoid travel altogether on Sunday. Speed limits were reduced on bridges between New Jersey and Pennsylvania, and a bridge in Delaware was closed. Roads closed because of accidents and downed trees and power lines, said Sean Brown, a spokesman for the Pennsylvania Department of Transportation.

Two of the airports serving New York City, Newark Liberty and Kennedy, had hours-long delays Saturday, as did Philadelphia's airport. Commuter trains in Connecticut and New York were delayed or suspended because of downed trees and signal problems. Amtrak suspended service on several Northeast 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.

Some train service had been restored by late Sunday, but delays were expected.

In southeastern Pennsylvania, an 84-year-old man was killed when a snow-laden tree fell on his home while he was napping in his recliner. In Connecticut, the governor said one person died in a Colchester traffic accident that he blamed on slippery conditions.

And a 20-year-old man in Springfield, Mass., who stopped when he saw police and firefighters examining downed wires, was electrocuted when he touched a wooden guardrail that had been electrified.

October snowfall is rare in New York, and Saturday marked just the fourth October day with measurable snowfall in Central Park since record-keeping began 135 years ago, the National Weather Service said.

But the unofficial arrival of winter was a boon for some. Two Vermont ski resorts, Killington and Mount Snow, started the ski season early by opening one trail each over the weekend, and Maine's Sunday River ski resort also opened for the weekend.