tonight on "nightline" -- a monster storm named isaac pounds the coast of florida. we're there and on the ground in new orleans as that city battens down nearly seven years to the day after hurricane katrina. and as the storm delays day one of the republican national convention, its stars are rolling into tampa, herman caine and chris christie for the fall. what does it look like when these political enemies get together for a grand ole party. plus, skywalkers an extreme youtube trend.

hundreds of feet high without a harness, inside a high-rise caught on tape. good evening, i'm cynthia mcfadden. tonight, tropical storm isaac is spinning straight towards the gulf coast rolling in each hour and expected to grow into a full-on hurricane as it churns towards new orleans. where, as fate would have it, the storm is predicted to hit seven years to the day that hurricane katrina brought the city to its knees. abc's ginger zee with the extreme weather team brings us the latest from the ground, tracking isaac. >> reporter: tonight, a storm that could be the first hurricane to hit the gulf coast in four years is aimed clearly at new orleans. are you ready? >> yeah, you know, we feel

pretty confident about the system. it's almost not comparable to what was in place when hurricane katrina came. >> reporter: today, we got up close to the colossal machinery, part of the 133 miles of levees that is now new orleans' first line of defense. see all the yellow boxes here. there's 11 new ones that shut down and separate the streets from lake pontchartrain. this time, when the water tries to get into the canal, they can shut it dn and keep it away from new orleans. >> we feel very confident with the system as designed tz. >> reporter: as i can as takes a slow approach, it's hard not to compare it to katrina. not because of the size but there are similarities. look at katrina's path when it slammed into the gulf. if the current you path holds,

isaac will take the same one. >> we're worried about flooding, we're worried about tornadoes. >> reporter: from florida, alabama, mississippi to louisiana, televisions are plasters with seemingly constant storm updates. officials are ready to show they've learned from mistakes of the past. >> louisiana governor bobby jindal will be holding a briefing. >> reporter: traffic has been backed up for miles where 50,000 people have been ordered to evacuate. hundreds of thousands from mississippi and alabama are being charged to leave, too. >> we encourage those people to get out of harm's way. >> reporter: but buddy and larry davis have hold it all before. they came back to rebuild only to get the oil spill in 2010, back then, he voiced his

frustration to george stephanopoulos. >> shut it down, shut it down. >> reporter: most of their neighbors have headed to higher ground but the vegases are determined to stay. >> if it was katrina, i'd be the first one out, but this one here, i'll be back to work. >> reporter: isaac has already cut a path of destruction through the caribbean. this time-lapsed animation shows the storm spinning and churning over the past week in its path to the u.s. in haiti, at least 19 deaths have been attributed to the storm, flooding and mud slides there now the main concern. there seems to be little worry when isaac rolled ashore on sunday in the florida keys. >> why are you guys out here? >> reporter: like most around here, they made it a reason to celebrate. but if the starbucks in new orleans today, where they have a permanent reminder of the flooding seven years ago, they don't laugh at these things

anymore. >> the whole feel in the city is a little different when you have something like katrina happen. >> yeah, we used to have hurricane parties, and now we take it a lot more seriously, if you need to leave, you leave. i think we do it even when we're told not to. >> reporter: here, they remember all too well what happened after katrina brushed the florida coast. then, it was only ka category 1 storm, in fact, it doesn't look that much more imposing than isaac now. but the warm waters of the gulf made it a category 5. >> i don't want to diminish the risk from isaac. it's still going to be a storm surge that will be did deep enough to cause loss of life and rainfall that will cause flooding. >> reporter: linda anderson lost her home in katrina. >> we had nine feet of water in our home here in lakeview. >> reporter: she moved back to it's old neighborhood just a few

months ago. >> we really hope that the corps of engineers did their job at the time. >> reporter: the corps says they have. but for those who still don't trust the levees, there's always this option, heading for higher ground cajun style. for "nightline," i'm ginger zee in new orleans. >> our thanks to ginger zee. well, up next, the storm also soaked the first day of the rbs republican national convention, where the biggest names of the gop came together to reunite under the tent. but are they really united? we're there next. [ female announcer ] they can be enlightening. hey, bro. or engaging. conversations help us learn and grow. at wells fargo, we believe you can never underestimate the power of a conversation. it's this exchange of ideas that helps you move ahead with confidence. so when the conversation turns to your financial goals...

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well, instead of opening with a bang today as it was scheduled to do, the republican

national convention opened with a rain check due to the encroaching storm, the real start of the convention has been postponed until tomorrow. and abc news has learned that governor romney will arrive tomorrow as well, two days earlier than planned. my co-anchor terry moran comes to us now from tampa at the convention center. terry, is there a sense down there that postponing was the right decision? it is, cynthia. they didn't want to host a disaster, they wanted to host a convention and there was the possibility of the latter. and also, not a lot goes on on the first days of the convention. not a lot of people watch them, frankly, on the first day. they will play a little catch-up by romney's arriving early but the distraction and the show goes on. >> the latest survey has president obama and governor romney in a dead heat. what does the governor need to do in the next three days,

terry, to pull ahead? >> i think we all sense this. he's got to connect. mitt romney has got to give the american people a fix on who he is, his character, his leadership, and what kind of president he would be. and that job begins right here with the delegates down on the floor here. this is a fractious bunch. a lot of different republicans. so his first test is to bring them together, and it is "your voice your vote," the republican convention. in some ways, it's like a family affair here. a gathering of the clan, the erld elders, the new generation all of it. they have their differences these republicans. and there was one official piece of business on this storm-shortened convention day. >> in session and called to order. ♪ what the up ♪ >> reporter: and this is what you might call the unofficial

convention where the ha hell-raisers and outside who made the primaries so raucous and unpredictable. michele bachmann, newt gingrich still firing things up. and this newcomer who streaked to the top of the polls before vanishing, herman cain. how are you doing? >> i'm okay. if you would have told me you were not wearing a tie i would not have worn one either. >> reporter: caine gets mobbed wherever he goes here. >> this is terry's show, you know. >> reporter: he has no big speech, you aren't taking center stage here? >> oh, no, when i was a candidate and we were doing those debate, governor romney is one of the most likable people out there. >> reporter: you like him? >> i like him.

>> reporter: so herman cain is on board, but not everyone is. >> we will get into the camp, believe me because we will become the camp eventually. >> reporter: ron paul spoke at the delegates but he will not engorse romney. there's one family spat that could get a little awkward. >> people at the convention are worried that how much trouble we would cause. >> reporter: what will paul's fervent libertarian followers do here? to find out, we headed to the convention floor. and here we are, the republican national convention. it's like it's always smaller in person than they look like on tv. roaming the floor, we kept meeting ron paul delegates, maybe newcomers just basking in it all. >> this is my first convention,

i'm happy to be here. >> reporter: troy christianson is from flower mound, texas, and he's a ron paul supporter who will stick to his guns now. how big is texas. >> we have 155 delegates and 152 alternates. >> reporter: all for romney? >> well, we'll all be for romney after the convention. >> reporter: and then we bumped into linda beane, she's the granddaughter of l.l. bean. >> i think it's a matter of trust and is he genuine with what he's saying. can we trust what he's saying? >> reporter: romney has a problem with trust? >> i believe he does. i don't believe ron paul does. >> reporter: at every convention like every family gathering who gets to sit where depends on who's in favor. who gets the best seats in the house. usually the candidate's home

state. with romney, which one is that, well, massachusetts right in front. but the best seat in the house -- michigan. and so it was there, right out front, in the massachusetts space that we found the most enthusiastic mitt romney supporter we've ever met. what would you tell people who are on the fence who don't know romney? what's the best thing about him? >> this guy is the midas, the king midas of family life. everything that he touches turns to gold. >> reporter: now romney has to reach out and touch the many branches of the republican family. they want that to come together, but they have a little work to do yet. ♪ >> so the plan by thursday night is that they will all be singing the same tune on key, and heading into the general

election where they will be pumped, no question about it, to take on president obama. cynthia. >> our thanks to you, terry. we know you'll be right down there telling us how they're doing. just ahead -- do not try this at home. inside a vertigo-inducing, skyscraper, heart-stopping youtube trend.

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it is the extreme version of look, ma, no hands. a dangerous trend where a daredevil gets their thrills by dangling from tall buildings, even skyscrapers without a harness or safety net. it's a viral craze not for the faint of heart. and we're pleased to welcome for the first time on this broadcast our abc news series with this "sign of the times." >> reporter: this is called roofing, a climbing craze going viral on youtube, and the guys to do it just might be insane. the concept is simple. find a building, a crane, anything that's tall and climb it. but it's what these roofers do at the top that's really crazy. hundreds of feet up, all without a safety harness. it started in russia, and it's spreading across eastern europe. climbers compete for the most

views online, each video getting more and more daring. it goes without saying, but do not try this at home. we wanted to find out just who would enjoy the vertigo-inducing effect of dangling off a tall building. turns out these guy. meet vitaly and jan. office workers. that's vitaly off the tallest bridge, about the height of the empire state building. no rope no helmet. we met them on what will soon be marked the tallest skyscraper. at the top, they were like kids in a candy store, rushing to go to the edge. he says he does this for the view. >> it's a feel of absolutely freedom. >> reporter: ask vitaly if he ever gets scared and he has a

simple answer. yes. i'm not stupid, he says. you have to be absolutely confident of your capabilities. roofing has gotten more and more popular in russia. some of the most popular and daring videos belong to this guy, artia, an adrenaline junkie. he specializes in skyscrapers. by day he's a computer specialist, but the 21-year-old has a knack for sneaking past guards, scaling rickity antennas. going where no roofer has gone before. a lot of people think you're crazy. do you think you're crazy? >> only a little bit. >> reporter: what does your mother think about it? >> she say to me that i'm crazy. she scream a lot. >> reporter: so how do they get up there? we decided to follow mars and sasha, a pair of students who never climb without their cameras. we hiked up a few flight of

stairs, crawled through an opening and stepped out to the sky. okay, it's not the world's tallest building, but even here, it was clear he was born to climb. the 20-year-old is actually studying law. but he's turned his passion into art. this photo won him a national competition. it's also what most roofers want -- fame. earlier, one of his friends slipped and fell to his death. he was just 18 years old. >> after that i decided not to do something very risky. >> reporter: but the danger hasn't stopped hundreds of young russians from climbing anything they can find. for the adrenaline. for the view, for that stunt that will get everyone talking. "nightline," moscow. >> that's terrifying. thanks for watching abc news. "good morning america" waiting for new the morning with