Thousands of Mainers headed to the stores Thursday to prepare for the possibility that they could be without power and heat for days – starting today.

A major storm packed with snow, sleet and freezing rain was expected to reach the state overnight after whipping its way from Texas through the Midwest and the Great Lakes region. At least 15 have died and power lines are out in portions of the country.

The storm is this year’s first real blast of winter to hit the United States.

Heavy snow and freezing rain stranded airline passengers, shut down schools and left thousands without electricity across the Midwest.

Unlike other parts of New England or the nation, most Mainers are prepared for the bad weather and the substantial discomfort that comes with it. Like every storm that has come before this one, they went out and bought groceries, batteries, bottled water and candles in anticipation of what the weather will bring.

“We want to be on the safe side,” said Leonard Mayhew of Winterport, who along with his wife, Terrie, purchased bottled water and batteries at Sam’s Club on Thursday afternoon. Their next stop was a grocery store. A couple of weeks ago, the Mayhews were without electricity for a few days when heavy, wet snow downed lines throughout the area, leaving thousands of households without power.

“This is Maine,” said Terri Mayhew.

The practice of stocking up on groceries and supplies the day before a storm is a Maine ritual that has been passed down through the generations. For hundreds of years, people have battened down the hatches and have ridden out the weather. Especially for the people who live in rural communities, where shoveling out from a storm may take a longer than in the cities.

“I’m not from New England, I’m from the south,” said Martha Williams of Hampden, who moved to Maine from Tennessee more than five years ago. “So when I hear a forecast like this, I head out [to the stores]. I think probably I get a little bit shakier than the natives, but I guess I’m taking on a few traits of New Englanders. Forewarned is forearmed.”

Also fresh in Mainers minds is the horrific ice storm in early January 1998, when it took a little more than a month for all of the households in the state to get their electricity restored.

For Barbara Libby of Columbia, storm preparedness is essential to her family ever since the ice storm.

“We were hit hard,” said Libby, who was buying batteries and light bulbs at Sam’s Club in Bangor on Thursday. “We were one of the last 100 families to get our power back.”

Patricia Brooks, owner of Shore Road Variety in Gouldsboro, was buying batteries at Sam’s to sell in her store starting today. She knows a few of her customers may need them today.

“We had some in the store so we thought we’d get some more,” Brooks said.

Bangor Hydro-Electric Co. and Central Maine Power Co. are warning customers that power outages are likely.

“Maine is the most heavily wooded state in the country so accumulations of heavy snow or ice always raise the threat of tree-related power outages,” said CMP spokesman David F. Allen. “Above all, if people see a fallen power line, they should stay well clear of it and report it. A downed line could be carrying a lethal charge of electricity without giving any sign of danger.”

Power outages were occurring in the Midwest on Thursday. About 270,000 customers were without power in the Kansas City area, 200,000 lost power in Oklahoma, and at least 63,000 others were without power in Michigan and Indiana.

“That makes this easily the worst storm we have ever experienced,” said Kansas City Power and Light spokesman Tom Robinson. “We need our customers to be prepared that this could last several days.”

According to Bernie Rogan, corporate spokesman for Shaw’s Supermarkets, northern New Englanders know how to prepare for bad weather. Customers at Shaw’s stores in Rhode Island, Connecticut and Massachusetts aren’t that experienced at it, he said, mentioning that he has the computer-generated numbers to prove it.

“The stores jam up,” Rogan said. “It’s like filling up the pantry to make it through the winter. Down here [Massachusetts], people panic. They run around like chickens with their heads cut off.”

Harold Daniel, an assistant professor of marketing at the University of Maine, said Mainers go to the stores before a storm “in anticipation of their needs.”

“You might not be able to satisfy them because of treacherous roads and icy conditions,” Daniel said.

Some of those “needs,” he quipped, could be chips, beer, soda and other snack foods.

“Chocolate ice cream,” Daniel added. “If the power goes out, I’m going to have to eat it in a hurry. That’s always a good excuse.”

Underneath those items in many shopping carts on Thursday, though, were the essentials.

“White bread, peanut butter and milk,” said Shaw’s Rogan. “Those are the basics that they really buy to make it through the next four days. And it’s the right thing to do.”

Add to that list cheese and meat, said Joe Derouin of Bangor, who along with Diane Francis had a list of items to pick up before the storm reached the area.

The storm, and what it brings with it, did not worry Sophia and Russ Beauchemin of Oakfield.

“We’re from Maine. It doesn’t bother us one bit,” Sophia said.

Compared to the 7 feet of snow that fell on Buffalo, New York, in two days last month, this storm is minor in comparison, Russ Beauchemin said.

“Just cozy in, snuggle in,” Sophia added. “It’s a New England thing.”

The Associated Press contributed to this report.