Seven million Texans were under boil water advisories Thursday after a pair of deadly back-to-back winter storms brought record-low temperatures, snow and ice that knocked out power plants and caused pipes to freeze.

Many have been without both power and clean drinking water for days.

About 350,000 homes and businesses remained without electricity in Texas late Thursday afternoon, according to poweroutage.us. While that's still a significant number, it's a major improvement over the 4 million outages reported Tuesday and the more than 2.5 million Wednesday night.

While power is back up for many, issues with municipal water supplies continue. More than 7 million people in Texas – or one-fourth of the population – were under boil water notices, according to The Associated Press.

"We were prepared, we thought," Austin resident Mariette Hummel told weather.com in an interview Wednesday. "We had some wood, some starter logs – as much as we could get. We had some gallons of water and some food. But we were not prepared for days and days of no power and no heat."

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Hummel was hunkered down with her 7-year-old son. As of Wednesday afternoon, they'd been without power for 60 hours, and without water for over a day. They were hoping the snow they piled up in their bathtub would melt, but so far it was too cold in the house for that to happen.

"I’ve never seen anything like this," Hummel said. "It’s staggering, to be honest. And we’re just trying to make it through."

Photos circulated on social media of icicles that formed on a ceiling fan inside a home. Grocery stores, if they're open, have long lines and empty shelves. People waited in line for hours to fill propane tanks. Hospitals struggled in the face of outages and at least one major airport shut down.

At least 20 deaths are believed to be connected to the weather this week in Texas, in addition to at least 18 others in 11 different states.

Here's a look at some of the major impacts from the back-to-back storms, named Uri and Viola by The Weather Channel.

The Weather’s Deadly Toll

From carbon monoxide poisoning to falls to car crashes to exposure, more than three dozen deaths have been connected to the extreme winter weather, according to the AP.

One of the deaths in Texas happened Monday night when 23-year-old Kevin Ayala used a generator inside to try to keep the home warm for his wife and young son, KXAS-TV reported. At least two others have died from carbon monoxide poisoning in Texas. Four people died in a house fire while their power was out, while others died from car crashes or exposure.

The Louisiana Department of Health reported three weather-related deaths. The latest was a 77-year-old man who drowned after he slipped and fell into a swimming pool in Calcasieu Parish. In Lafayette Parish, a 74-year-old woman died from exposure after she wandered away from her home and a 50-year-old man slipped on ice and hit his head.

A man was found dead Tuesday in a snowbank in northwest Indiana, according to the Porter County Sheriff's Office.

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A 25-year-old woman was found dead in a mobile home with no electricity or heat in western Kentucky. Another person in Kentucky died of carbon monoxide poisoning, and a third was killed in a car crash.

Arkansas resident Jessie Roberts, 69, died as he attempted to save a calf stranded on an icy pond at his farm, the Logan County Sheriff's Office said.

In Illinois, one person was killed and another injured when an awning at an off-track betting site collapsed under the weight of snow, according to the Chicago Fire Department.

Other deaths included vehicle crashes in Tennessee and Missouri, a man who fell through ice in Oklahoma, a child who fell through ice in Tennessee, three people who died in a tornado Monday night in North Carolina and four who died from carbon monoxide poisoning over the weekend in Oregon.

Water Outages

Residents in Houston, Austin and several other cities were still under boil water advisories – if water was available at all – as of late Thursday afternoon.

The situation was affecting not just households and businesses but also schools, fire stations and health care facilities.

Hospitals in Austin, for example, were stressed by the outages.

"Because this is a statewide emergency situation that is also impacting other hospitals within the Austin area, no one hospital currently has the capacity to accept transport of a large number of patients," St. David's South Austin Medical Center CEO David Huffstutler said in a statement, according to the AP.

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Officials noted that it was hard to know exactly how many people were completely without water.

Austin Water Director Greg Meszaros estimated the number in his city was "tens of thousands," according to KUT-Radio.

Residents were advised to make sure they know how to shut off their water in case pipes start leaking when it comes back on.

The water issues stem from frozen water lines, power outages that took water plants offline, and a large number of people leaving their faucets dripping. The boil water notices are necessary because whenever water pressure drops there is a chance that groundwater could get into the system, Meszaros said.

Houston's William P. Hobby Airport reopened Thursday morning after being shut down due to a lack of water.

Water outages plagued other states as well.

Louisiana was struggling with 36 water outages in 18 parishes Wednesday night, according to a news release from Gov. Jon Bel Edwards. More than 175 boil water notices were in effect in 39 parishes. In all, more than 1 million people were affected, the governor said.

Edwards sent a letter to the White House requesting an emergency declaration. The state is also grappling with the coronavirus pandemic, as well as still recovering from multiple hurricanes that hit the state last year. Five named storms made landfall in Louisiana, and three of them made NOAA's list of 2021 billion-dollar disasters.

Power Outages

More than 800,000 homes and businesses were still without power in eight states, according to poweroutage.us.

Besides Texas, the states with the most outages as of about 6 p.m. EST Thursday were Mississippi with more than 135,000; Louisiana with about 100,000; Oregon with 89,000; Kentucky with 70,000; and West Virginia with about 60,000. Widespread outages were also still being reported in Virginia, Alabama and Ohio.

In some areas, power was restored after snow and ice earlier in the week, only to be knocked out again.

Many of the outages, especially in Texas, were the result of frozen equipment at power plants and increased demand that forced rotating power outages to keep the grid from shutting down completely. Officials there said the outages that remained Thursday evening were the result of ice and tree damage.

Other Impacts

While the first storm, Uri, is no longer, Winter Storm Viola has dumped several inches of snow in parts of the mid-Atlantic and East and caused ice accumulations in Virginia and North Carolina Thursday.

The governors of North Carolina and Oklahoma have requested federal emergency declarations.

The snow and ice weakened structures and led to hazardous driving conditions.

The top deck of a parking garage collapsed Thursday monring in Lexington, Kentucky, WKYT-TV reported.

In Tennesssee, 12 people were rescued from boats after a dock on the Cumberland River collapsed under the weight of ice and snow, the Nashville Fire Department said in a news release.

The 100-yard dock was already in the water when crews arrived. Boat and dive crews found 12 people in vessels that were sinking and/or taking water. All were safely rescued.

Two airports in Jackson, Mississippi, are shut down due to ice. The Jackson Municipal Airport Authority said Jackson-Medgar Wiley Evers International Airport and Hawkins field will remain closed until at least Friday.

Air travel also continued to be impacted at several major destinations, according to FlightAware. At least 689 flights are canceled today at Dallas-Fort Worth International Airport, more than 200 each at Baltimore/Washington and Washington Dulles, and more than 100 at LaGuardia.

Schools in several districts in the Washington, D.C., area canceled classes Thursday, including Anne Arundel, Arlington, Berkeley and Charles counties.

The CDC said the weather is causing delays in the delivery of COVID-19 vaccines. Some states have shut down vaccination sites and testing centers.

The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.