Buying has pushed the jackpot to half a billion dollars. What to do if you get lucky tonight. But first, the nightline 5. Number 1 in just 60 seconds. Good evening. Thanks for joining us. We begin with the shocking claim from north korea that it tested a Hydrogen Bomb. It sent diplomats scrambling and the u. S. Launched planes to verify. But out on the campaign trail it gave candidates a chance to appear president ial. When the news broke, we were behind the scenes on a sixday bus tour with one of the gop frontrunners, ted cruz. Abcs tom llamas has the story. Reporter last night an alarming claim from north korea. State televisnnouncing they had suc tested a Hydrogen Bomb to protect north korea from warmongers like the u. S. For hours after, the world waited nervously. But finally, after analyzing the shock waves, the white house calming fears. The initial analysis is not consistent with the claims that the regime has made of a successful Hydrogen Bomb test. Reporter today on the campaign trail the candidates weighing in. North korea is a paranoid isolated nation. They are when you have a Hydrogen Bomb if thats true you are a threat. This underscores the gravity of the threats we are facing right now. Reporter we spent the day with republican candidate senator ted cruz. I thank you. Reporter here in iowa where the caucuses are just 26 days away. How are you doing . Reporter ted cruz has spent a lot of time and resources here. Welcome to iowa. Reporter and the polling is in his favor. Trump and cruz are neck and neck. Far ahead. With rubio trailing at 14 and carson at 10 . But some republicans worry cruz is too polarizing too unwilling to compromise with congress to win the general election. How can you be a president and hate the democrats and hate the culture of washington so much and be effective . I dont hate the democrats. Its Hillary Clinton who describes her, quote, enemies as republicans, as half of the country she considers her enemies. Im praying for you. Thank you very much. Reporter his supporters coming out in droves. Some even moved to tears when they meet him. You got emotional speaking to senator ted cruz. Youre still emotional. Why are you crying . Because we need such a change in our country. Reporter hes on a sixday, 28stop tour of iowa in an effort to secure every corner of the hawkeye state. Talk to me about your momentum in iowa. We spend a lot of time just one on one asking for the voters support. People expect to look you in the eyes. Theres an old joke in iowa, are you voting for so and so for president . No no i couldnt possibly. Ive only met him five times. Reporter but nationally the landscape is different. Trump trumps the competition. Cruz is just at 18 . At one Campaign Stop a cruz supporter wanted answers. How are you going to convince independents and democrats to support you when we know the numbers are against us nationwide . I think the way we do it is as reagan said in 1980. You paint in bold colors not pale pastels. Reporter getting close to trump in the polls doesnt come easy or without a fight. On television and in newspapers trump questioning if senator cruz can even be president since he was born in canada to an american mother. Trump even suggesting democrats would have a field day challenging cruzs president ial eligibility if he gets the nomination. How do you run against the democrat whoever it may be and you have this hanging over your head if they bring a lawsuit . A lawsuit would take two, three years he says hes a naturally born citizen because his mother was u. S. Born a u. S. Citizen, and as a result hes a naturalborn citizen. Well i hope hes right. Reporter moments after stepping off his campaign bus this morning, cruz put it to rest. The child of a u. S. Citizen born abroad is a naturalborn citizen. Reporter donald trump a couple weeks ago talked about your ethnicity and your religion. Now hes talking about, you know that you were born in canada. Not criticizing it but saying that you could have problems with that. Why do you think hes doing that . Oh look im not going to try to psychoanalyze donald trump. You know my view if others do you think he sees you as a threat . Youd have to ask him that. A lot of folks in the media would love to see donald and me get in a giant food fight. And im certainly not going tone gauge in that. I hope donald wont either. Reporter if im a trump supporter in iowa or anywhere else in the country, why vote for ted cruz . Well listen i think my record is stronger than his. And i think my record is vonger than every other republican candidate running. Reporter cruz and trum have certainly played nice so far even seemed to agree on one of the biggest issues of the Campaign Season immigration. What do you do with the 11 million undocumented immigrants in the u. S. . Deport them . Or they stay here . You enforce the law. You deport them. We will secure the borders. Well build a wall. We will triple the border patrol. Well increase fourfold the fixed wing and rotary wing aircraft. We will end sanctuary cities. Well put in place a strongly verified system at the workplace. We will end Welfare Benefits for those here illegally. We can solve this problem. Reporter tonight on cnn trump saying cruzs immigration plan sounds very familiar. He said and we will build a wall. So now hes tak my idea for the wall. Im glad hes taking it. I think its the right thing to do. Reporter so how is cruz catching up to the trump train . One of the cornerstones of cruzs support here in iowa and around the country is his faith. We need those prayers desperately. Reporter cruz is also trying to show voters another side. Staying strong with the help of a fitbit. Do you go up and down steps . That is awesome. Reporter and making voters laugh with comedy bits like his impressions. Tonight in iowa it was jerry maguire. You had me at hello. Reporter monday it was clint eastwood. Make sure to hang him high. Byebye. Have fun storming the white house. Reporter he also does a mean billy crystal. You look marvelous. Not bad. Reporter the 45yearold republican candidate graduated from princeton, then harvard law, near the top of his class. A champion debater and an actor on stage. Skills that helped him deliver his message to washington with a twist. I do not like green eggs and ham. I do not like them sam i am. Repz announced he was running for president last more i believe in the power of millions of courageous conservatives rising up. Reporter his cuban immigrant father waited backstage. Incredible. Reporter cruz met his now wife heidi while on the campaign trail for george w. Bushs 2000 white house run. Married nearly 15 years, they have two young daughters, caroline really been a joy to get out to the states and just meet with thousands and thousands of people who share our values and who are turning out to hear the message of ted cruz. Reporter he admits its hard being away from his family and tries to bring his girls on the road when he can. Whats it like to be away from your daughters when theyre so young . Its the hardest part of the cacampaign. I mean our girls, caroline is 7, catherines 5. We try to bring the girls on the road as much as we can. Theyre coming out. Theyll be joining us here in iowa on friday. What theyre on the bounce theyre bouncing off the walls. They have fun with it. My 5yearold catherine two days ago woke me up in my hotel room my ipad ringing that catherine was facetiming me from her ipad. Is it tough you . Dont get that time back. You miss a lot of moments in their lives. But as you noted, thats also why youre doing it. I couldnt look my daughters in the eyes if i had the ability to do something to stop it to bring america back and i didnt stand up and lead. So thats a very big part of why im doing this. A shining city on a hill. Reporter tonight cruz working late into the evening, making his case and trying to convince Republican Voters to put their faith in him. [ applause ] for Nightline Tom llamas in storm lake, iowa. Next an upclose look at the impact of Global Warming de a glacier. And later, the huge Powerball Jackpot that has so Many Americans hoping to wake up millionaires. To severe Crohns Disease is tough but ive managed. Except that managing my symptoms was all i was doing. And when i finally told my doctor, he said humira is for adults like me who have tried other medications but still experience the symptoms of moderate to severe Crohns Disease. And that in clinical studies the majority of patients on humira saw significant symptom relief. And many achieved remission. 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Were standing in the middle of the melting vakna glacier. And scattered all throughout this glacier are massive vertical sinkholes that are treacherous. They go hundreds even thousands of feet into the earth, where ice is melting faster and faster as water levels in the atlantic rise even more. Throughout geelogic time and certainly for the last 2 million years, weve gone through ice ages and warm periods, and glaciers come and go over time. What were seeing right now, thoughs a real rapid increase in the rate of thinning and melting that were seeing. And thats related to humaninduced Climate Change. Reporter gearing up for this treacherous journey has been a multiday expedition. Just call these guys glacial life savers. They are an elite unit comprised of volunteers. Experienced ice climbers. And true masters of this forbidding terrain. They train on icescapes like this. Then descend into the depths of the coldest climates braving perilous weather conditions to reach people trapped in the most intimidating of landscapes. Guides on the ice, theyve canceled hollywood too. Keeping crews safe on blockbusters from star wars to interstellar and game of thrones. We joined them right in the heart of this icy wonderland. Walk up that wall of ice. And its perfectly safe . Yeah. You hesitated. Reporter ready to lock and load. Its my turn to attack the slippery slope. Pulling myself up by my own weight picks on my hands and feet the ice giving way beneath me. Getting a small taste of how difficult, dangerous, and exhilarating it all is. And finally i got up. Whoo reporter then by car and foot our Team Trekking nearly a mile through water, rocks, and ice, all in arctic temperatures. The landscape, dazzling. Dangerous. And disappearing fast. Losing an average of 11 billion tons of ice per year. This satellite picture taken in 1986 and this one 28 years later. Iceland is melting, and that water has to go somewhere. When youre talking about changing sea level youre talking about impacting the tremendous population around the world. Reporter including miamis coastline. Those waters already climbing an inch a year. And take a look at this. If sea levels keep rising in two centuries some scientists warn that city could be completely underwater. Charleston too. Even new york. And these other lowlying areas around the globe, entire ways of life now threatened. So were plunging far below the surface of the ice in a neverbeforeattempted live event. Hey, guys. Go for it. Go ahead and start ice climbing. Reporter going deep into this glacier. Passing bands of darker ice like the rings of a trees showing ash and debris from volcanic eruptions from ages past. Vakna, a glacial sinkhole a massive pipe for melting ice that can be thousands of feet deep. And all this melting ice eventually ending up in the ocean. This is remarkable watching them scale this massive ice wall. It takes tremendous ut its all to get to the bottom. What do you expect theyll see when they get down there and what will we all see . This is one of the most interesting and least known parts of Glacier Research which is how does water from the surface get to the base and help lubricate the base to make the glacier flow faster . Reporter its a long treacherous way down but finally guys i want to check in with you. This is amy again pu made it to the bottom . Thats right. Tell me what youre seeing. Describe what youre looking at. Everything is awesome. He went ahead with im surrounded by black and blue ice. And i can tell you one thing. I have a challenging climb in front of me. Reporter but some Scientists Say not nearly as challenging as the problem we face slowing the per being of this vital hidden world. Amy robach in iceland. Up next what you could do if you win the massive Powerball Jackpot. 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So many of us tonight hoping thats all it takes to become a multibajillionaire. Tonights Powerball Jackpot is half a billion dollars. The biggest one in more than two years. Heres abcs kayna whitworth. Reporter luck be a powerball tonight. Just how nice an extra 529 million bucks could be. 47 2, 63 62 11. Reporter tonights winning numbers and 17 is the powerball. The cash payout worth a minimum of 306 million in cold hard cash. Even though it comes on a sillylooking oversizeed check. There you go. Okay. Its crazy. Reporter just like the one julie weeks from michigan received when she won the Powerball Jackpot last november. For 23 years she worked at a fiberglass factory. Are you leaving your job . Oh, i quit automatically. I was done. Reporter that jackpot was worth just over 310 million. But the former factory worker opted for the lump sum payment and pocketed a mere 140 million bucks after taxes. I was having a really bad night at work, thought, well i might as well check my numbers while im sitting here waiting for my lunch. And thats when i realized that i was the winner. I didnt believe it. Reporter so what do you do with the winnings . Tackle those new Year Resolutions for starters. If your goal is to get fit, maybe you want to look fabulous like Gwyneth Paltrow or kate hudson hudson. With 500 million you can hire celeb trainer to the stars Tracy Anderson at her monthly rate for you, your family and friends for life. Or if you simple ry why want to get out more tonights jackpot will get you nearly 25,000 trips around the world. Skys the limit, but Financial Experts say keep your Purse Strings tight by waiting six months or longer before buying anything. According to a 2015 study, 44 of winners spent their entire winnings within five years. And losing their riches is only one bad outcome for lottery winners. Like abraham shakespeare, who won 30 million in florida in 2006 was found murdered three years later. A woman who had befriended him is currently serving a life sentence. But if tonights drawing left you emptyhanded there is a next time. And a fine art to choosing the right numbers. Dont pick numbers based on your kids birthdays or your wedding anniversary. In fact, dont pick the numbers at all. 70 to 80 of Powerball JackpotWinning Tickets have been computer picked. But if you insist on picking the numbers, try these 8, 54 14 39 13. Those are among the most frequently drawn numbers in the past four years. If no one wins the big pot tonight, the next drawing is saturday when the grand prize is estimated to be worth 675 million, the largest jackpot ever. For nightline kayna whitworth, abc news new york. Of course if you win you could tweeted me jujuchangabc because i have a few other ideas on how you can spend that money. Thanks for watching abc news. World news now is coming up soon with overnight breaking news. Tune in to Good Morning America tomorrow and as always were online at abcnews. Com. Good night, america. Amy, this roast is so tasty. Yes, honey it is delicious. Amy thanks robert made the Police Blotter this week. Wow what went down, man . A shootout with some smack and crack heads . No, no. Nothing so exciting. It just said, mailbox defaced. Unit responded. He was the unit. Pat oh. You know, robert, i always wanted to ask you something. What is that, sir . Why do you touch your food to your chin before you put it in your mouth . Dad no, no. Thats okay, amy. You know i noticed that, too. Why do you do that, robert . Itsits nothing. Its just a little habit of mine. Thats all. Yeah. He hardly ever does it. Peter ah, thats all right. Every family has their oddball. With us, its mom. But why do you do it . Are you using your chin to test the temperature of your food . Oh, thats silly hank. Hed have a big red mark on his chin every time the food was too hot