Americans from the Gulf of Mexico to the Canadian border were pummeled by a historic winter storm on Monday as heavy snow, freezing rain and Arctic temperatures made highways impassable, closed airports and crippled the electricity supply in Texas on one of its coldest days in decades.

The dangerous storm, part of a series of weather systems sweeping the country this week, resulted in accumulating snow and ice across a wide swath of states that rarely see wintry precipitation, including heavily populated areas of Texas. The storm knocked out power to more than 4 million households in Texas, raising questions about the durability of the power grid in the United States’ second-most-populated state, and one of its fastest growing.

The electricity issues, which authorities warned could in some places persist for days, resulted in blackouts that prevented residents from being able to heat their homes, cook meals or work remotely. The power cuts even knocked out electricity at a Houston-area warehouse where 8,000 doses of coronavirus vaccine were stored, forcing health officials to rush to distribute 4,000 of them to anyone they could before the doses spoiled.

“The Texas electric system is facing an unprecedented power shortage situation due to the extreme winter weather impacting the entire state, including Houston & the region,” CenterPoint Energy, which serves more than 2 million customers in the Houston area, said in a statement Monday. “Texans’ electricity consumption needs have far surpassed current power generation.”

The severity of the blackouts, which analysts said were a sign that governments and utility companies did not prepare adequately for the storm, were traced to soaring consumer demand for heat as well as the inherent dangers that extreme cold poses for Southern power systems that were built to handle summer heat over frigid winter.

“To see this kind of impact on a wide scale across the grid is very unusual, particularly in the winter,” said Rebecca Miller, a Texas energy analyst for Wood Mackenzie consulting firm. Miller said the rolling blackouts on Monday are the only things that prevented the state’s electricity transmission from collapsing. “But I was expecting a little bit more preparation. . . . What we really saw was a bit more of a reactive response than a proactive one.”

In Texas, rolling blackouts were also reported in the major population centers of Houston, Dallas, Austin and San Antonio, where snow and sleet reached the Alamo. Snow even accumulated on the beach in Galveston, a city where residents are far more accustomed to hurricanes than they are to wintry weather.

As power outages in Texas multiplied on Monday afternoon, even as the snow had stopped in most places, Gov. Greg Abbott (R) went on Twitter to push back at suggestions that the state was facing a catastrophic power failure. Abbott also activated the National Guard to help usher residents to 135 warming locations.

“The Texas power grid has not been compromised,” Abbott wrote. “The ability of some companies that generate the power has been frozen. This includes the natural gas & coal generators. They are working to get generation back on line.”

But across the state, even residents of major cities were forced to rethink some of the basics to get through the day.

Sayra De La Cruz, 37, said she and her boyfriend woke up in Houston on Monday morning without electricity and no water because of frozen pipes. Without a way to flush the toilets, she decided to collect snow and melt enough of it for two flushes.

“It’s definitely hard because the shoveling in itself — that’s some cardio right there,” said De La Cruz, adding that she was filling both of her bathtubs with snow so it can melt slowly.

Oklahoma Gas and Electric, the state’s largest utility, also announced Monday that it implemented intermittent controlled service interruptions — an unprecedented measure for the company. The blackouts were in effect for about two hours, but they may return depending on capacity, spokesman Brian Alford said.

As the storm moved north into the Ohio Valley on Monday afternoon, so did the problems.

In Louisiana, icy conditions prompted authorities to close dozens of highways and bridges, including sections of Interstate 10. Icy roads were reported in at least 74 of Mississippi’s 84 counties, which Gov. Tate Reeves (R) told the Weather Channel was complicating efforts to restore power to more than 61,000 residents. In Arkansas, Little Rock was paralyzed by a two-inch-per-hour snowfall rate, the National Weather Service reported.

In Kentucky, Gov. Andy Beshear (D) sent the National Guard door to door in remote rural communities to urge residents — some of whom have been without power since a storm last week — to move into shelters. Beshear urged everyone to take the storm seriously.

“We did not make it through almost a year of a pandemic to lose people to a snow or ice storm,” Beshear said in a televised address. “You have more ability to work remotely. You have more ways to connect to one another and get things done. We are looking at coming out of this pandemic by summer, so please do not let the next couple of days or this week be what injures you or causes the loss of a loved one.”

At one point Monday, the Weather Service had winter storm warnings issued from Brownsville, Tex., along the U.S.-Mexico border to Caribou, Maine, a distance of more than 2,500 miles.

In New York, where every county was under a winter weather advisory or warning Monday night, Gov. Andrew M. Cuomo (D) urged residents to stay home.

But the residents of the South have been hardest hit by the storm, which meteorologists warn could be replicated in the coming days as another storm system is predicted to follow a similar track and collide with a cold snap.

The bitter cold is affecting about 30 states, with temperatures as much as 50 degrees below normal.

George Bush Intercontinental Airport in Houston dipped to 17 degrees early Monday, the coldest reading observed there since Dec. 23, 1989. Tuesday’s morning low could be even more frigid: the Weather Service forecast is 11. The wind chill on Tuesday morning is expected to be 1.

“Dangerous life and property threatening bitterly cold air will continue even as the precipitation ends,” the Weather Service in Houston wrote early Monday.

Farther north, wind chills early Monday plunged as low as minus-40 and minus-50 in parts of Nebraska, Kansas and Colorado.

In Texas, the power outages were tied to record-high demand, an electrical grid that is independent from surrounding states, low natural-gas supplies, along with sky-high prices, and reduced output from the state’s wind turbines.

The Electric Reliability Council of Texas (ERCOT), the umbrella organization that oversees the state’s power grid, warned that it would continue to implement mainly short-term, rolling blackouts across the state.

There have been three in­stances of rotating outages during an Energy Emergency Alert because of weather events in Texas, with the first occurring in 1989, according to ERCOT. Energy demand in the Lone Star State is expected to hit an all-time high.­

On Monday evening, 4.3 million outages were reported in Texas — more than one-third of customers in the state, according to poweroutage.us.

“Every grid operator and every electric company is fighting to restore power right now,” ERCOT president and chief executive Bill Magness said.

Miller, the Texas energy analyst, said the strain on Texas’s power grid was more reminiscent of the types of failures that could occur during a major hurricane. But even there, Miller noted, those hurricane-related power failures are usually limited to a specific corner of the state. This threat encompasses nearly the entire state.

Jesse Jenkins, an assistant professor of engineering at Princeton’s Andlinger Center for Energy and the Environment, said the extreme weather pushed Texas’s energy capabilities past the breaking point as chilled Texans tried to heat their homes.

The state was already dealing with higher seasonal demand because of the pandemic, with more people at home drawing power instead of clustered in work­places during the day, Jenkins added.

The outcome of the current power crisis will force a discussion about the future of the Texas energy system and raise questions about the state’s outlier approach to power, Jenkins told The Washington Post.

“It’s not just an event you move past; there were significant discussions about the 2011 blackouts, and last summer’s blackouts in California,” Jenkins said. “These are the kinds of events that have significant policy and political ramifications.”

Texas remains the only state to operate on an independent power grid, which is run by ERCOT. The state’s electricity market runs on an energy market, which Jenkins said works like Uber’s surge pricing: Rather than power companies being paid to make sure they have generators on call during times of high demand, they are paid only when they provide power.

In Austin, Cody Miller, 36, had been without power since about 1:30 a.m. Monday. By 10 a.m., the temperature in his East Austin home was hovering near 50 degrees, with no clear information from the utility companies about when power might be restored.

It was the second time in a week he had lost power after enduring a 10-hour outage on Thursday. “There’s no real communication and 311 is pretty much down,” said Miller, who works in the telecom industry.

In parts of Dallas, residents lost electricity and water because of frozen pipes.

Brandon Friedman, 42, who lives in northeastern Dallas, had been without power since about 2 a.m. and had no water despite leaving the faucets open slightly to drip.

Speaking to The Post from his car where he was charging his phone, Friedman described his driveway — blanketed in five inches of snow — and his regret at leaving one household item behind for the new residents when he moved from Virginia back to Dallas four years ago.

“I left our snow shovel hanging up in the garage in Virginia because we weren’t going to need it in Texas,” Friedman said.

Andrew Freedman, Matthew Cappucci, Alex Horton, Jason Samenow and Meryl Kornfield in Washington and May-Ying Lam in Houston contributed to this report.