A crippling Arctic blast continued to wreak havoc across a large swath of the United States on Tuesday after a snowstorm left more than a dozen dead and millions without power, with officials in some places saying residents might be in the dark for days.

And it’s not over. A second storm had begun taking shape Tuesday night, aimed at the nation’s southern tier and some of the same hard-hit areas, according to The Washington Post’s Capital Weather Gang.

Among those killed were a 10-year-old boy who fell through ice near Millington, Tenn., and a woman and a girl who died of carbon monoxide poisoning in Houston after a car was left running in a garage to keep them warm, according to police. A tornado associated with the storm system also struck North Carolina, killing at least three and injuring 10.

Wind-chill watches and warnings stretched from the Dakotas to the Gulf Coast as the coldest of this Arctic outbreak so far hit Tuesday morning, with Dallas, Houston, and Oklahoma City all posting their lowest temperatures since at least 1989.

With nearly three-quarters of the continental United States blanketed by snow, at midafternoon Tuesday, there were 3.8 million still without power in Texas, and thousands more in 16 states, including Oregon, Kentucky, ­Louisiana and West Virginia, according to the website ­PowerOutage.us.

In many places, temperatures were colder than in Alaska, the National Weather Service in Kansas City noted in a tweet, where Anchorage saw a comparatively balmy low of 20 degrees. In Kansas City, the temperature was ­minus-10 Tuesday morning, and St. Joseph, Mo., was minus-21, compared with 5 degrees above zero in Fairbanks.

Texas was hit especially hard. In Corpus Christi, a coastal community in the southern part of the state, preparations are typically underway to host an influx of students for spring break at this time of year. But on Tuesday morning, the temperature had plunged to 19 degrees, causing pipes to burst and straining the city’s ability to care for its residents.

“This cold has been extremely difficult on us because we are a coastal community of 300-plus days of warm weather a year,” said Mayor Paulette Guajardo, who has been on the job only a month. “We are just completely unaccustomed to it — we are a bathing suit and shorts community, but we are going to get through it, and we are going to be stronger because of it.”

Texas's independent power grid was crippled under high demand and damaging weather after a historic cold snap hit the U.S. over Presidents' Day weekend. (John Farrell/The Washington Post)

Like the rest of Texas, Corpus Christi has been hit by sustained power outages, with Guajardo estimating that at least a third of her city’s 325,000 residents have lost power. She and numerous officials around the state said the Electric Reliability Council of Texas (ERCOT) “failed” Texans by not doing enough to prepare for the cold snap.

ERCOT operates the state’s electric grid.

“There was a lack of communication,” Guajardo said. “On one hand, we were told there was going to be ‘rolling blackouts.’ But there was never rolling blackouts. There were just blackouts, and so you had residents who just were not prepared.”

The storm also threw the nation’s coronavirus vaccination plans into disarray as inoculation sites across the country are shut down because of power outages and hazardous weather, while shipments are delayed because of poor road conditions.

The Texas Department of State Health Services said shipments would start arriving Wednesday, adding, “No one wants to put vaccine at risk by attempting to deliver it in dangerous conditions.” The delays also affected states that were not heavily hit by the storm because they rely on vaccine doses shipped from those that were. The grocery chain Publix stopped taking appointments for vaccinations in Florida, South Carolina and Georgia, citing the shipping delays.

A spokeswoman for the Centers for Disease Control and Prevention said federal officials are “projecting widespread delays in COVID-19 vaccine shipments and deliveries over the next few days” tied to poor weather in distribution hubs out of Louisville and Memphis.

Officials in Harris County, which includes Houston, rushed to deploy more than 5,000 doses after a storage facility lost power and the backup generator failed early Monday. They distributed the vaccine doses to Rice University, a local health system and the county jail to use.

In Oklahoma, those 65 and older who canceled their vaccine appointments opened up slots for teachers and adults with comorbidities, who were not due to begin receiving shots until Feb. 22, according to the state’s rollout plan.

Walmart temporarily closed more than 500 stores in Texas and elsewhere in the South. Immigration courts and other civic business around the country ground to a halt.

In Texas, officials pointed fingers about who was responsible for the large-scale failure of the state’s power grid, as strained gas-fired and nuclear power plants and frozen wind turbines left more than 4 million without power in the storm’s immediate aftermath, including some who had been in the dark for more than 24 hours. Utility officials are warning Houston residents that the power outages could last “several more days.”

Residents in other states, including Kansas and Nebraska, also experienced rolling power outages as utilities struggled to cope with the strain on their systems.

“I just got out of the hospital a few weeks ago with acute respiratory failure. I was sleeping with my oxygen on and woke up to the power being out,” said Allison Campos, who lives in Fallbrook in northwestern Houston. “I am terrified. I stop breathing, and my heart stops when I’m sleeping. I have one tank for short trips. I’m supposed to be on three liters, but I have it set to two to conserve.”

Stephen Streiker and his wife, Jacqueline, spent Monday night huddled inside their frigid apartment in the Las Colinas section of Irving, Tex., trying to keep warm.

The two of them were “down to one battery pack and candles and a 7-pound miniature dachshund for warmth here,” Streiker said in an email Monday night. Reached early Tuesday morning, he said the outage was going on 28 hours, and they were planning to leave their apartment to seek heat elsewhere.

“Whatever stored up warmth we had in [the] apartment is gone. I’m guessing inside temp is around 50, and dropping. It is 1-degree outside,” Streiker said. “We are going to have to decamp. 28 hours+ with no electricity.”

He said many of his neighbors had slept in running vehicles in their parking structure in a dangerous attempt to keep warm overnight.

Texas Gov. Greg Abbott (R) declared reform of the state’s grid operator an emergency item for this legislative session, and the speaker of the Texas House called for hearings on what went wrong.

ERCOT, the operator, blamed the icy weather for affecting thermal power plants, which include gas, coal and nuclear.

“Far too many Texans are without power and heat for their homes as our state faces freezing temperatures and severe winter weather,” Abbott said in a statement. “This is unacceptable.”

In Oklahoma, homeless shelters opened up extra beds, and Tulsa residents had raised $1.5 million since Friday to put up hundreds more people in hotels and motels. Outreach organizations planned to begin sending housing assistance coordinators to hotels and motels to try to secure long-term placements for as many of the homeless as possible.

Paramedics were called to a homeless encampment in Oklahoma City on Tuesday to treat a man who was suffering from frostbite on his feet. They took the man to a hospital, but others at the camp stayed behind after declining rides to a city heating center.

One resident had built a fire to thaw bottles of water as the temperature in the city fell to minus-14 on Tuesday morning, the coldest since 1899.

Cyrus Whittaker, who has lived in the camp for 3½ months, said the last couple of nights outside have been “miserably cold.” Residents have done whatever they can to keep warm, he said, including “huddling up in a single tent to make sure we were not going to freeze for the night.”

He was working with representatives of the city’s Homeless Alliance for things the camp needs — propane, firewood and food.

Living outdoors is rough, he said. “It’s not at all what you would think as your ancestors went through here settling here as pioneers,” Whittaker said. “It sucks, and that’s putting it the polite way.”

In Kentucky, Boyd County Judge Executive Eric Chaney asked the state’s governor to send in the National Guard as hundreds of residents were living in precarious conditions without power after an ice storm last week downed hundreds of trees and knocked out 44 percent of the county’s electricity.

Many were able to make it through the first few days without power with generators, but they were running low on fuel when a second ice storm hit Monday. National Guard members rescued more than 30 residents and transported them to the county’s warming center.

Now, Chaney said, the county is bracing for another storm — with three to five inches of snow expected.

In Mississippi, Gov. Tate Reeves (R) issued a state of emergency Sunday before snow quickly covered the roadways, creating hazardous driving conditions Monday. While the sun came out Tuesday afternoon, the Mississippi Department of Transportation took to social media to encourage Southern drivers unused to the conditions to “stay home” and “don’t be fooled” by the sunnier skies.

In New Orleans, where the city had already scaled back its Mardi Gras festivities because of the coronavirus, some residents and visitors still tried to celebrate the town’s famous holiday. On Esplanade Avenue, Jeanne Nathan, 79, and Bob Tannen, 83, sat outside early Tuesday dressed in big winter coats, to catch people passing their “house float,” featuring a fiberglass cast made by Tannen, of “Marlina,” the largest blue marlin caught in the Gulf of Mexico by a woman.

It was 27 degrees, a cold made worse by the tropical city’s humidity.

“Even though I once lived in New Hampshire, this is colder,” Tannen said.

Knowles Adkisson in Little Rock, Andrea Eger in Tulsa, Nick Oxford in Oklahoma City, Katy Reckdahl in New Orleans, Jef Rouner in Houston, Sarah Fowler in Jackson, Miss., Silvia Foster-Frau and Arelis R. Hernandez in San Antonio, and Brittany Shammas, Matthew Cappucci, Paulina Firozi and Dino Grandoni in Washington, D.C., contributed to this report.