Tonight, the brutal Arctic blast that's sweeping across the country. Snow, ice, and frigid temperatures are having a major impact on travel. Will the extreme weather influence the race for the White House just as the first votes are cast? More than 100 million Americans are on alert for dangerous winter weather. Sub-zero conditions in the middle of the country. Unrelenting snow near the Great Lakes as much as 3 feet of snow expected. Also in the northeast, coastal flooding. Tens of thousands now without power. As residents in the south brace for a new storm with snow, rain, and ice. Our weather team times it all out. The final countdown to the Iowa caucuses, Donald Trump confident, saying the weather will have zero effect on the outcome. Pundits say it's a race for second place between Nikki Haley, who is gaining ground, and Ron DeSantis, who vows to stay in the race. His supporters going door to door for votes. Our new ABC news poll, How Electible are the Republican Candidates? Rachel Scott in Iowa, Rick Klein at our big board to break down the numbers. Shocking allegations. Homeland Security claims the Texas National Guard blocked federal agents from trying to rescue three migrants who drowned in the Rio Grande.

One congressman says Texas authorities have blood on their hands. Tonight, Texas officials tell a much different story. A showdown on Capitol Hill as Congress nears a deal on short-term funding bills. But with no aid for Ukraine, ammunition is running low. Ukraine's top diplomat vows to fight Russia with shovels if they don't get new weapons. One town in Iceland on the brink as fast-moving lava destroys homes there. The Iowa principal who came face-to-face with a school shooter succumming to his injuries today. Dan Marberger is credited with preventing a wider tragedy. His daughter says, That's just dad. Plus, the NFL quarterback who became an unlikely hero off the grid iron. The story behind this picture and his new fan for life. And remember the name, Chandler Hughes. He's now joined an elite club featuring some of the world's most intelligent minds at just six years old. From ABC News, World headquarters in New York.

This is World News Tonight.

Good evening, everyone. Thanks so much for joining us on this Sunday. I'm Lindsay Davis. We are on the eve of the Iowa caucuses, the first contest of the 2024 Race for the White House. Republican candidates are making their final pitches in frigid conditions, but we do begin with breaking news and a record-breaking Arctic cold Snap sweeping across much of the country. More than 100 million on alert for that dangerous winter blast. Blizzard-like conditions reducing visibility and making roads impassable in Buffalo and other parts of Western New York. New York's governor extending a travel ban in Erie County. The cold air now sweeping into the northeast, where residents along the Coast are still cleaning up from flood damage. High winds plunging tens of thousands into the darkness in Wisconsin and Michigan. Parts of the south bracing for dangerous conditions. Shoppers stocking up at the grocery store in Memphis, Tennessee. Meteorologist Samara Theodore is standing by with the forecast. But first, Victor Kendo leads us off from Iowa, where temperatures are expected to fall well below freezing.

Tonight, a brutal Arctic blast sweeping across much of the country, bringing dangerous windchills from the plains to the Midwest and triggering heavy Lake effect snow along the Great Lakes. More than 100 million people are on alert for bitter cold, snow, and ice, as a new winter storm now takes aim at the South. Tens of thousands remain without power in Wisconsin and Michigan. Here in Iowa, residents digging out after a massive blizzard blanketed parts of the state with over 10 inches of snow. Upstate New York bearing the brunt of the high winds and blinding snow, whiteout conditions like this, forcing the governor to extend a travel ban in Erie County. The storm already dropping more than a foot of snow with more heavy snow expected through the night.

Buffalo anywhere from 6 to maybe about 10 or 11 inches, and there will be in the most persistent snow bands as much as 2 feet.

Those treacherous conditions seen at the Buffalo Bill's Highmark Stadium. The wild card game between the Bills and Stealers postponed until Monday. Cold air now sweeping across the northeast, following a powerful storm that brought huge waves and triggered flooding. Residents in the south racing, too, as a new storm now moving across the Rockies has residents stocking up.

Thinking that weather's going to be horrible. I hope it's not, but he's convinced us to go to the grocery store and wipe them out.

This brutal winter weather, complicating travel today, too, with some 1,300 flights canceled. Here in Iowa, we are counting down to what will be the coldest caucuses on record with much of the state remaining below zero all day tomorrow.

Lindsay? Wind chill is about minus 40 degrees expected. Victor, thank you. Let's get right to ABC meteorologist Samara Theodore, who's tracking all the dangerous weather for us tonight. Hi, Samara.

Hi, Lindsay. That's right. So Lake Effect snow has been crippling in parts of Western New York, dumping a foot already, and they're in for more. Snowfall rates just south of Buffalo are about one to two inches per hour. Where these strong snowvans set up, blizzard conditions are leading to pure whiteouts. Of course, this wouldn't be possible without that bone-chilling air. Windchill alerts are stretching from Montana to the Southern tip of Texas. Some cities in Iowa feeling like minus 30 for the caucus tomorrow morning. Meanwhile, tracking the latest cross country storm, Dallas to Shreveport, therein for icy conditions with snow possible from Little Rock to Nashville. This same system finishes up in the northeast on Tuesday, and it could be bringing snow.

Lindsay? All right, Samara. Thank you. Now to the other major news. Tonight, after months of campaigning, the Iowa caucus just one day away. Former President Trump on the stump today, making his final pitch to voters, urging them not to get complacent. And Florida governor Ron DeSantis and his supporters pushing forward, going door to door despite the frigid temperatures as Nikki Haley overtakes him in the polls. Abc's Rachel Scott is on the ground in a frigid Iowa.

Tonight, a confident Donald Trump swooping into a frigid Iowa. Less than 24 hours until the caucuses, holding his first and only scheduled event in a week.

We have a lot of people here.

If this is any indication, the storm has had zero effect.

South of Des Moines and Indianola, hundreds breathing brutal temperatures, feeling like 35 below zero to see the former President and the 2024 Republican front runner.

We work through broken glass to see Trump.

You would?

Yeah.

And the caucus for him, too?

Yes. The weather doesn't matter. Saving America is what matters.

Trump holding a dominant 28-point lead in a New Des Moines Register, NBC News Poll. Nikki Haley and Ron DeSantis now in a desperate race for second place. The former South Carolina governor now edging out DeSantis by four points.

This is truly cold, but we're going to keep on going anywhere and everywhere. We're going to go all the way until the last hour.

Trump taking notice, targeting his former ambassador to the UN. She's really not much of a Republican.

She's certainly not magged.

That brutal weather derailing Haley's first in-person event in Dubuque today. But DeSantis campaigning in the same town just minutes away.

We've been at people's doors. We've been doing events. We've been garnering a a huge amount of support, and now it's time tomorrow to bring it to fruition.

We got another one. In Des Moines, his supporters going door to door, trying to pick up his slack in the polls. Our Mary Alice Parks caught up with them. How long are you guys going to be out here doing this?

Until it gets there. Until it gets to 10 below, right?

No, it's seven below right now, so we'll see.

Even though he is the front runner in this race, Donald Trump has visited this state far less than his rivals, only having 36 stops here. Compared that to Florida Governor Ron DeSantis caucus with more than 170 campaign events. Tonight, the former President urging his supporters not to be complacent and to turn out tomorrow, Lindsay.

Rachel, thank you. Now, let's turn to ABC Political Director Rick Klein with a new breakdown of polling numbers from Iowa and across the country. Former President Trump topping his rivals on several key measures. Rick, what could this mean for the weeks ahead?

Lindsay, Donald Trump goes into the caucuses tomorrow night, extraordinarily strong in Iowa and across the country. This is our poll with Ipsos, a national poll, and it shows 65% of Republicans say Donald Trump is the strongest leader, 50 points above his rivals. 45, 19, best represents your values. It's Trump in a landslide. Similarly, best understands your problems. Donald Trump is the candidate nationally. And on the key question of electability, It is Donald Trump by a lot. 68% of Republicans say Donald Trump is the best choice to go up against Joe Biden. Now, when it comes to tomorrow night, Donald Trump actually lost Iowa in the caucuses eight years ago. That's not going to happen again, almost certainly. But how it happened is actually instructive. When you're looking at the returns coming in tomorrow, Ron DeSantis visited all of Iowa's 99 counties. There are places in the state, heavily evangelical counties in particular, up in the northwest corner, where Donald Trump came in a distant forth last time around. A lot of reasons to think that's going to be hard to replicate, but Ron DeSantis hopes that that means that he can overperform expectations. For Nikki Haley, her focus is the cities and the suburbs, a lot of votes in places like Des Moines and Iowa City and Davenport.

Marco Rubio actually did really well there last time, and Nikki Haley is just hoping the late momentum helps her there. Now, as for Donald Trump, the name of the game is basically doing better everywhere, and there's a lot of reasons I think that's going to happen, including the fact that there are 100,000 more Iowa Republicans than there were eight years ago. The Trump campaign is convinced those are MAGA Republicans.

Lindsay. All right, Rick. Thanks so much. And please join me in World News Tonight, anchor David Muir tomorrow night, starting at 07:00 PM Eastern for in-depth coverage of the Iowa caucus on ABC News Live. You can watch wherever you stream. Now, the urgent search for two Navy Seals missing off the Coast of Somalia after a night time boarding mission gone wrong. Let's bring in ABC's Ike Jachi in Washington. Ike, what new details are we learning tonight? Well, Lindsay, officials say this all happened during the boarding of a vessel by boat on Thursday. The two Navy sailors were reported missing at sea while conducting operations in the Gulf of Aden, off the Coast of Somalia, where Iranian-backed Houthi militants in Yemen have carried out more than two dozen attacks against commercial ships. But officials say the SEAL mission was not related to those strikes.

Now, officials say the operations were meant to disrupt the flow of weapons supplies to Yemen.

A former US official described the nighttime boarding operation as one of the most complex and dangerous operations that Navy sailors can carry out. Lindsay? And of course, massive protests in Yemen. Ike, thank you. And one final note tonight from Iowa, and it is sad news. The Perry high school principal hailed a hero for risking his life to protect his students during a shooting has died. Dan Marberger was critically injured during the January fourth attack. An 11-year-old middle school student also died, and six others were injured. Here's ABC's Morgan Norwood.

Tonight, the Hero Iowa high school principal, Dan Marberger, who was shot while protecting his students during a school shooting 10 days ago, has died. Authorities say the Perry high school principal of 28 years throwing himself in harm's way, distracting the teen shooter just long enough for many students to escape the school's cafeteria. His daughter, Elizabeth, writing on a GoFundMe page originally set up for his recovery that her father fought hard and gave us 10 days that we will treasure forever. Marberger was one of seven people shot when a 17-year-old went on a rampage, killing a 6th-grader before taking his own life. Two students are still recovering in the hospital. Tonight, the beloved high school principal remembered as a father of five, grandfather, husband, and friend. This handwritten card delivered to his hospital room, reading, Not all heroes wear capes. Some are the school principal. And Lindsay, Iowa's governor, Kim Reynolds, says the entire state is devastated by Principal Murberger's passing. She's ordering all flags in the state to be flown at half staff.

Lindsay? Certainly a hero, Morgan. Thank you. Now to Congress, nearing a deal to avoid a government shutdown, but it does not include aid for Ukraine. It comes during a critical point in the conflict. Ukraine's top diplomat tells ABC News that time is running out with Russian forces threatening to take more territory. Abc's Tom Suvi Birge is in Ukraine for tonight.

Tonight, Russia outgunning Ukraine and threatening to take more territory. With future American support for Ukrainian troops held up in Congress and with frontline forces running low on ammunition. Ukraine's top diplomat telling us time is running out, but his country will never bow down to Russia.

Even if we run out of weapons, we will fight with shovels.

Ukraine fortifying its defenses, with officials warning of a fresh Russian offensive in the coming weeks. Troops telling us Russia has more firepower on the ground and in the air, and way more exploding drones. Those drones proving deadly for Ukrainian troops. Casuities at this hospital are mounting. They're now bringing up to 100 heavily wounded Ukrainian soldiers to this one hospital in a single day. That's a rise of up to 30 say doctors, compared to a few weeks ago. But the UK giving Ukraine a boost. Prime Minister Sunak visiting Kyiv Friday, pledging $3 billion more in military aid.

Whatever the price of supporting Ukraine is now, The price of fixing the mess in the world if Ukraine loses will be much, much higher.

Lindsay, news breaking tonight. A Ukrainian lawmaker claiming Ukraine has shot down a Russian military surveillance plane and a bomber over the Black Sea. There has been no comment from Moscow.

Lindsay. Tom, thank you. We turn now to the war between Israel and Hamas, marking 100 days of death, destruction, and suffering. Protest gathering around the globe, from the White House to London, to demand a ceasefire. In Tel Aviv, tens of thousands of people rallied in support of the more than 100 hostages, including some Americans, still being held by Hamas. Next tonight, a deadly controversy at the US border. A woman and two children drowned in the Rio Grande as they tried to enter the US from Mexico on Friday night. Us border officials say Texas military officers prevented them from helping. But Texas officials are denying those allegations. Here's ABC Zorin Shah.

Tonight, Homeland Security and members of Congress blasting the state of Texas. They say for denying federal agents access to a part of the border where they were trying to rescue three drowning migrants Friday night. Mexican authorities recovering the bodies of a woman and two children in the Rio Grande overnight near Eagle Pass, Texas. Representative Henry Qualar, who represents Eagle Pass, says the Texas Military Department and Texas National Guard did not grant access to border patrol agents to save the migrants. On Wednesday, Texas authorities built a fence with gates and razor wire, taking control of a 50 acre park along the Rio Grande, blocking federal border agents from entering. A move the city's mayor empathetically rejected. That is not a decision that that we agreed to.

This is not something that we wanted.

This is not something that we asked for as a city.

Two days later, the Justice Department asked the Supreme Court to intervene. In the court filing, the Justice Department saying, Texas has effectively prevented Border Patrol from monitoring the border. Representative Joaquin Castro slamming Texas's governor, saying, Governor Abbott's inhumanity has no limit. Everyone who enables his cruelty has blood on their hands. While the governor's office has referred questions about those migrant deaths to the Texas Military Department. In a statement, the Texas Military Department saying they searched the river after Border Patrol contacted them, leading them to send soldiers with night vision goggles and flashlights to look for people in distress, but they did not find anyone. Lindsay, the state of Texas responded to the Justice Department's Supreme Court filing. They denied that they barred federal agents from the border.

Lindsay. Zareen, thank you. There's still much more ahead on World News tonight this Sunday, including a deadly balloon accident in the Southwest. And mold and lava threaten the town in Iceland as a volcano erupts again. Next tonight, we're just getting word of a deadly balloon accident in Southern Arizona. The hot air balloon crash landed in the desert in Eloy. That's about 50 miles northwest of Tucson. Four people were killed. One other person was critically injured. The cause of the accident is not yet known. The National Transportation Safety is leading the investigation. Moving to Iceland now, and some spectacular images from a volcano that has erupted for the second time in less than a month. Molten lava flowed into a town about 30 miles from the capital. Multiple homes caught fire, but defensive barriers kept most of the lava away. The town of nearly 4,000 residents had been evacuated before the eruption. No injuries have been reported. When we come back, the NFL quarterback and his new number one fan. To the index now, and a royal succession. Today, Denmark's Queen Margaret signed her advocation, citing health issues. She formerly passed the throne to her son, now known as Frederick X.

Margaret, now 83 years old, is the first Danish monarch to relinquish the throne in nearly 900 years. Now to a quarterback who made a clutch play off the field. The Green Bay packers Jordan Love went out for a drive on Friday and saw Lucy Kurosky. Her car was stuck in a snowbank. She knew who he was and admits she was fan-girling. Love helped push her car out of the snow and later posed for a selfie. When we come back, the six-year-old who's accomplished something most adults cannot. Finally, tonight, are you smarter than a six-year-old? Maybe not this one. Chandler Hughes of Houston, Texas, isn't your ordinary six-year-old. You're looking at one of the newest, youngest members of the Mensa Society, the largest largest high IQ society in the world.

My favorite subject in school is math. I like to do multiplication. Three times three equals? Blue. We used to call them the king of numbers. I have.

Chandler's mom, Angelique, says he started reading when he was just one year, nine months old.

I read for 62 months.

That's a lot of months.

She knew her son had a special gift.

We He got him IQ tested, which allowed him to skip kindergarten, and he went straight to first grade. But the teacher discovered that he could do reading and math levels that were above first grade, and he was moved to second grade levels.

Chandler also plays the piano.

I'm all about raising a well-rounded human being, well-rounded child.

To him, it's all just part of being a kid.

I just want to draw and enjoy some time with my friends.

Chandler already knows what he wants to be when he grows up.

A medical doctor because I want to help people when they're sick.

Excitement is already building about his future.

He always tells me he wants to save the world, so we'll see what happens.

Bright future there. Thanks so much for watching. I'm Lindsay Davis. Have a great night.

Thank you for making World News Tonight with David Muir, America's most watched newscast.