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 down 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, theyade 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... turn to us. if you need anything else, let me know. wells fargo. together we'll go far.

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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 tha >> reporter: what will ? to find out, we headed to convention floor. and here we are, the republican national headedo 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 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. ♪