on our broadcast tonight, river rising. right now, they're going door-to-door along the mississippi, urging thousands of people to get out while they still can. now the disaster plan goes into effect. getting the picture, the bin laden videos. the image of a terrorist in his retirement years that the u.s. wants the world to see. the autism update. a surprisingly high rate of autism in a new study of children overseas, but what do we make of the results here? and our "education nation" report tonight. the girls getting help powering up their technological life. and which modern era american president kept a card collection of thousands of jokes?

"nightly news" begins now. captions paid for by nbc-universal television good evening. it's a flood of historic proportions along the most important waterway in the united states. by one estimate, the water moving down the mississippi right now from memphis and points south is moving at a rate of 2 million cubic feet per second. they haven't seen this much water in places like memphis since the post-depression era of the 1930s. from cairo, illinois, south to new orleans, they're watching the water, trying to predict where it will crest. this epic fight to save people and property combines nature and science. they won't be able to save everyone, and they know it. we start off with two reports tonight. janet shamlian starting our coverage tonight in memphis, good evening. >> reporter: good evening to you. they're prepping for these floodwaters in a number of communities along the mississippi, but tonight, it's

here in memphis, that is a city under siege. the crest is this evening. and floodwaters will be rising to levels they haven't seen here in more than 60 years. the rising river is cresting tonight, having already swamped hundreds of homes and giving memphis a true case of the blues. >> last thursday, we walked all the way up to the fence up there, and now it's gone. i mean -- i can't believe this. >> reporter: the waters are even lapping at the end of downtown's famed beale street where the mighty mississippi is usually a half-mile wide, it's now three times that. >> we're going to live through this for another few weeks, and it's going to be a nasty one, going to be an expensive one, and there are going to be some dangerous environments to deal with. >> reporter: much of the area is awash in snake invested muddy soup. >> we're definitely concerned about some of the debris and

stuff that the water has brought. >> reporter: there will be no quick relief for submerged neighborhoods like this one. the national weather service said floodwaters won't even start to recede for another 48 hours, keeping hundreds in shelters. >> where's your mommy? >> reporter: and some of their best friends in safe harbors of their own. >> they're out of their environment, so we want them to be as comfortable as possible. >> reporter: 200 pets have been taken in here. their owners will return when they can. downstream in mississippi, the engorged river is now leaking through the levees. a sign here the worst is yet to come. >> it will come and it will go. we hope it doesn't do more damage than it has. >> reporter: anxiety rising with the floodwaters for cities and towns where the river runs through it. janet shamlian, nbc news, memphis. >> reporter: this is anne thompson. this spring, the mississippi river refuses to be tamed. some 30 miles northwest of new orleans, a deliberate rush of

water at bonnet carre, louisiana, this morning. officials opening 28 of the spillway's 350 gates, sending some of the swollen mississippi on a six-mile journey to lake pontchartrain, to prevent new orleans from being inundated like memphis. part of the plan following the great flood of 1927. >> there's going to be thousands of people who are affected by this very directly by having either their homes or their property flooded, and that's with everything working perfectly. >> reporter: levees, essentially giant walls made by man or nature, try to contain much of the mississippi where towns and cities crowd parts of the river. today, 4 million people are in the flood zone. what were once natural flood plains are now valuable farmland. the nutrient rich soil feeding america and the world. development that's erased 35

million acres of wetlands, nature's flood protection, an area the size of illinois. >> this is history repeating itself. we have lost our floodplains and wetlands, and people are at risk again. we can't let that happen. >> reporter: today, the mississippi is not just spreading beyond its banks. it's rushing into its tributaries already swollen by rain. that means the yazoo river in mississippi has nowhere to go but into homes and fields as well. flooding that the army corps of engineers says could last until the end of the month. as the flooding moves south, the army corps of engineers has asked permission to open a second spillway near baton rouge. if permission is granted, several communities will have to be evacuated including morgan city and houma. brian. >> and the water keeps on going, anne thompson, janet shamlian before that, part of our team in memphis to start us off tonight, thanks. now we want to turn overseas and pakistan and the ongoing friction with the u.s. over the

killing of osama bin laden. the pakistani prime minister said today it's disingenuous to blame pakistan to, quote, being in kohouts with al qaeda. at the same time, the pakistani government has launched an investigation into how bin laden could have lived in a military town undetected for so many years. peter is on the ground in islamabad tonight. good evening. >> reporter: brian, good evening to you. tonight, u.s. officials tell nbc news, pakistan is prepared to give american intelligence officials access to osama bin laden's three wives or at least to share information that has been gathered from the women's interrogations. these home videos seized in last week's raid and selectively released by the u.s. government show osama bin laden like we have never seen him before. bin laden looks less like the world's most feared terrorist and u.s. officials say, more like an old man obsessed with his own image, watching himself

on tv, and with these clips with the audio removed, stumbling through his speeches, at times looking off camera as if for direction. today pakistan's prime minister spoke out for the first time about his country's nubt to find bin laden himself, calling the incompetence ubsurd. >> no other country in the world and no other security agency has done more to protect al qaeda than the isi and the armed forces. >> reporter: and he insists that pakistan reserve the right to retaliate with full force if its sovereignty was violated again. still the question remains, how did bin laden avoid capture for five years in this military town? just over two hours from the capital? >> we think there had to be some sort of support network for bin laden inside of pakistan, but we don't know who or what that support network was.

>> reporter: u.s. officials tell nbc news pakistani intelligence did provide the u.s. with information that ultimately led to bin laden, helping track down his trusted courier, but adding to tensions between the two countries, the alleged outing of the cia's top operative in pakistan last week, apparently intended to undermine america's covertactivities here. >> there's a al qaeda structure alive and well in pakistan. we need pakistan's cooperation to go after it. >> reporter: and brian, one report suggests the children who had been living at bin laden's compound were home schooled, they rarely ventured outside, and tonight, the prime minister announced that compound will be demolished. >> peter alexander in islamabad for us. thanks for that. we're debuting a new nbc news poll on this broadcast tonight, and it shows an overwhelming majority of americans support the decision to kill, not capture, osama bin laden. there's also news about the

president, jobs, the economy. with us from washington is our political director, chief white house correspondent chuck todd. good evening. >> reporter: good evening. in moments like last week, presidents do acquire political capital. it's no different for obama, but he didn't acquire a lot. here is his job approval. in our poll, 52%. that's a small bump, not a big one from the last time we tested he was at 49% last month. he got a big spike among americans with his approval rating on foreign policy, 57%, all-time high in the poll, but the reason he didn't get a bigger spike in the overall job rating, look at the numbers on the handling of the economy. just 37% approve of that. 58% disapprove. you talk to many analysts in both parties and they say there are two reasons for that, gas prices. they're high, and it's having a drag on the president. the president got a bump on some of his character attributes as far as the country is concerned. over 50% say he has strong leadership qualities, he's got the ability to handle a crisis,

he's firm and decisive, all the things a president wants going into re-election, but he's under 50% in achieving his goals, uniting the country, or sharing your positions on the issue. as for the bin laden effect on views on the war in afghanistan, only 20% agree with the statement that says it's time to pull all troops out now, that the killing of bin laden means the threat is gone. 72% agree with the president's position that says, yes, bin laden is dead, but the threat has not gone away and troops may have to stay in afghanistan. and finally, there's a big loser in the poll, the government of pakistan. 72% do not believe the government there. they believe somehow the government knew bin laden was in their country. >> speaking of our looming election year here, tomorrow night, we're going to do a update on where all the potential republican candidates stand. there was news on newt gingrich today. >> the former speaker of the

house is going to do something that no speaker of the house has ever done before. he's going to run for president. he let it leak that he's going to announce it on twitter and facebook on wednesday. he had already been testing the waters, but he's probably the most well-known person now in the race. we'll see. he's going to have a tough row to go, as we tested in our own poll. he's got a lot of negatives to overcome. >> chuck todd in the d.c. bureau. thanks, as always. the ford f-150 pickup has been the best selling vehicle in america for years, so just the hint of trouble today got the attention of a lot of americans. federal safety officials said they have widened an investigation into the truck. 2.7 million of the model years '97-'01. the problem is straps that hold the fuel tank which may be prone to rust and breakage, leading to fire risk. there have been more than 300 owner complaints about them. again, so far, just an investigation. we'll keep you posted. it's the way they used to talk about coca-cola and gm. the annual ranking of the most

valuable brands is out tonight, and there's a new king of the hill. that's apple, subplanting google. here's the rest of the top ten. you may recognize all of those logos except for maybe that number nine between marlboro and ge. that's china mobile cell phone service. 70% market share in china. think for a moment about how many customers they have. and speaking of the number four brand on the list, mcdonald's, a big change coming to its restaurants. just when we got used to the molded swivel chairs and fiberglass tables that are comfortable for about as long as it takes to plow into a pile of mcnuggets, they're spending over $1 billion to make their restaurants more chill, more comfortable, more laid back. more starbucks than mayor mccheese. look for wooden tables, muted colors, and faux leather seats coming soon to a mc's near you, and you can get fries with that.

and we have family news. meredith vieira made it official today. she's coming off the morning shift to enjoy life and her own family a bit more. she'll of course stay in the nbc family. when that happens in june, another beloved family member of ours, ann curry, moves up to cohost. natalie morales will replace ann as morning news anchor, and savannah guthrie leaves the white house beat to host the third hour of "today" each morning, so we managed to keep it all in the family. we'll take a break. when we come back, what parents can learn from a major new study of autism. and later, helping girls get a headstart in a field dominated by men in our "education nation."

back here tonight with news on a new study that is going to add to the debate over a disorder than seems to be surging and causes so much anxiety for families who wonder if their child has it. talking about the spectrum of autism disorders. tonight, a new study overseas

seems to show the instance could be even higher than anybody first thought. our report from robert bazell. >> are you ready to listen? >> reporter: autism interrupts social interactions and covers a broad spectrum from terribly severe to mild. today finds the mild form might afflict many more students that assumed. the incidence of autism could be as high as 1 in 38 in children, twice as high as most previous estimates. >> autism is more common than we think, and there are a lot of kids out there who are actually doing somewhat well in mainstream schools but can do even better if they're provided some assistance. >> reporter: researchers carried out the study in a suburb of seoul, south korea. the study was easier to do there because of korea's universal health care and education. but the scientists say there's no reason to think the results would be different elsewhere. most previous research examined medical records of children

whose parents sought help, but this study sponsored by "autism speaks" focused on 50,000 of the 7 to 12-year-olds in that suburb, those in regular schools as well as those in special education classes. >> we knew we would find more kids in this population. >> reporter: judith thought her daughter amy was doing fine until the third grade when amy started having problems with other children. eventually, she was diagnosed with asperger's, a mild form of autism, and therapy has gotten her back on track. >> now that i recognize how i'm different from other people, it's really helped me a lot. >> reporter: and these scientists say today's studies suggest there's lots more kids like amy around the world who might benefit from the extra help that can follow a diagnosis of autism. robert bazell, nbc news, new york. when we come back tonight, the discovery in california. they called him the great communicator, but tonight for the first time, a special

glimpse into where all that material came from.

as you may know, like tools to a carpenter, the best comics in the entertainment business tend to their jokes carefully. joan rivers famously has every joke she ever wrote and delivered filed away on a 3 x 5 card. guess who else did that? ronald reagan. while we remember him more as the 40th president than a comic, he didn't get that great communicator title for nothing. in getting ready for the centennial celebration, the reagan library came across a treasure. his material, jokes, quotes, one-liners, all kept in a box. author and historian douglas brinkley has edited a book out tomorrow called simply "the notes." tonight, he tells us what he found. >> thank you. >> anybody who knew ronald reagan knew he kept the note

cards because he would keep them in his desk, he would pull them out, and they were the tools of his trade. he would record the jokes he heard and liked the best. some he invented himself. in speeches, it wasn't done with the teleprompter like you do today. these note cards are reagan's security blanket, if you like. >> it is said that politics is the second oldest profession, and i have come to realize it bears a great similarity to the first. >> some of the jokes have a conservative flavor to them, about the wastefulness of the government. >> balancing the budget -- >> you don't spend more than you take in. >> it's like protecting your virtue. you have to learn to say no. >> sometimes it was one-liners or old-style dean martin roast humor. there's a generational aspect to some of his jokes, but in many ways they're timeless. we live in this electronic age. everybody's e-mails look the

same, but when you see these cards, you can feel the moment when reagan was doing it or the cross-out or the different color of pen. it became, i think, one of the most interesting presidential artifacts i have ever seen, because if you're really looking for the hand of a president and how his mind is working, all of these note cards together in a way, give you the magic of ronald reagan's rhetorical skills. >> historian and author doug brinkley on the comedic trove of ronald reagan. up next here after a break, the power of technology in the hands of teenage girls. one woman's brainstorm that's making a big difference.

and finally on this monday night, a woman who saw a problem and created a solution that's making a real difference for teenage girls. young women who have the desire to learn about one of the fastest growing fields and a great route to future jobs but don't always have the access to the tools they need.

in tonight's "education nation" report, kristen welker has a story on a good idea that is closing a critical gap. >> two minutes. >> reporter: this isn't your typical computer science class. this is compugirls. a two-year program to teach teens of color skills like programming, podcasting, and even how to build computer games. >> i think the field of science in general and engineering is very intimidating for female. >> reporter: 16-year-old carolina used to be intimidated, too, but then compugirls changed everything. >> before the program, i had not touched a mcintosh computer. now i have the motivation to study and know that i can be something in life. >> maybe you'll create a magazine. >> reporter: dr. kimberly scott a professor at arizona state university, started compugirls in 2007. her goal, to increase the number of women in science, technology, and math. so far, the program has reached 200.

>> technology is becoming more and more important in terms of whatever occupation an individual chooses to pursue. >> reporter: but it's an uphill battle. recent studies show more than three-fourths of those earning bachelor degrees in computer science are in men. the strides are evident, compugirls also participate in internships at big companies like intel. professional exposure that is teaching jamie the sky is the limit. >> i would like to be one of those women in the technology field in the future. >> reporter: recent graduate kyra tyler is already putting her computer skills into practice. small businesses are asking her for help. >> they're asking me to make websites for them, help get rid of viruses. >> reporter: a program just for girls that is creating a new generation of tech-savvy women. kristen welker, nbc news, phoenix. and that's our broadcast for

this monday night as we start off a new week together. thank you for being here with us. i'm brian williams, and of course, we hope to see you right back here tomorrow evening. good night. life in the fast lane. that perk that's about to end for tens of thousands of drivers. the news at 6:00 starts