battle for iraq. we meet some americans on the ground in the fight against isis. the major offensive under way to retake a key part of that country. dramatic rescue. a toddler saved from a deadly car crash. as seen through the eyes of first responders. high alert. home explosions on the rise in colorado and what's behind the dangerous trend. something you might not expect. and making waves. a group of teens attempting a feat few would dare and learning life-lessons along the way. >> announcer: this is "nbc nightly news" with lester holt. substituting tonight, carl.

it appears the militant group known as isis is about to face a big setback taking control of tikrit. the battle raged for days between isis and iraqi forces. even some americans are on the ground including former military trying to deliver a blow to the group that still controls huge parts of iraq and syria. nbc's bill neal yea starts us off. good evening. >> good evening, carl. we've witnessed the fight against isis firsthand today. we've been with kurdish troops who are pushing isis back and they're being helped by american volunteers. iraqi militias are taking on isis and iraqi government source told nbc news isis is losing tikrit. isis is under heavy fire. rockets and mortars raining down on isis positions.

these are iraqi militias armed and backed by iran and spearheading the attack on tikrit. isis is dug into the city center, and surrounded. the militias are already celebrating, but they won't move in until they get reinforcements. isis has booby-trapped buildings and roads. iraq's defense minister is predicting victory, and isis is clearly being pushed back on many fronts. kurdish troops are making gains. they took us to their front line with isis. from sandbag positions, we saw isis flags flying over two villages the kurds are attacking. there's been sporadic firing from isis positions here in the last few minutes. but there's no doubt that the momentum of this war is against isis here, and for now. but the history of war in this part of iraq shows that can

change, and change quickly. >> i just get a boom, and i duck down had glass go all over me. >> reporter: some americans have joined the fight against isis. micky came from colorado. not as an official u.s. adviser, but as a lone volunteer. >> i'm just here to help get rid of isis to hit them where it hurts, in the roots. >> is that what you're doing? >> that's what we're doing. there are people being raped, beheaded enslaved executed thrown off of buildings. i'm not cool with that. >> reporter: jeremy from mississippi is a retired u.s. soldiers who served in iraq. he's back another volunteer. how is it as an american to be fighting isis? >> it's something that needs to be done. because isis they're a cancer to the world. if it doesn't stop here, it's going to keep on spreading. >> reporter: they claim more american volunteers are coming to join them as the battle for saddam hussein's hometown reaches a decisive moment.

now, those americans insist they have not been sent here by the u.s. government which has pledged no combat troops here. they say they're not mercenaries because they're not being paid. and they're not terrorists certainly, they say isis are the terrorists who should be confronted here before they threaten the homeland. back to you, carl. >> big kneeley tonight, thanks to you. incredible video of the little girl saved from the wreckage of a car that crashed into that frigid utah river. we're now seeing the rescue as it unfolded through the eyes of first responders as they frantically tried to save the life of lily grossbeck. >> reporter: it's a heart-stopping look at the nine moments that saved baby lily's life. after she spent 14 hours upside down in a half submerged car. with no hesitation first responders raced to the wreck, splashing into the icy river.

on the body camera video, you realize the 18-month-old is inside. along with her mother who police say died when the car crashed. straining to get the baby out, they do. >> pass her up! go go go! >> reporter: rescuers moving fast breathing hard. >> come on baby. >> reporter: she's in trouble, and they know it. >> she's definitely hypothermic. >> reporter: they sprint to the ambulance where they try to get her blood circulating. >> come on sweetie. >> reporter: wrapping her in a blanket, performing cpr. >> we're almost there. are you getting a pulse? >> reporter: finally they reach the hospital. the video ends with lily grossbeck in the care of the doctors who helped save her life. >> underwater, yes.

>> reporter: it's a breathtaking first-person perspective from the responders who jumped into action. >> everybody knew what they had to do. everybody was in the right position. everything happened just right. >> reporter: baby lily's story has captivated the country. her recovery and her return to her family, safe and healthy. >> i'm just really blessed, and i'm just glad to have my daughter here with me. i'm overwhelmed with joy right now. she's just a miracle to me. >> reporter: from start to finish an incredible story of heroism and hope. holly jackson, nbc news, los angeles. tonight we're learning more about the damage from one of the pacific ocean's most powerful storms ever cyclone pam has brought casualty and damage with the brunt of the impact felt by a tiny nation just east of australia. here's our report. >> reporter: the first images from the battered south pacific islands of vanuatu, homes ripped

apart, trees shredded sailboats shoved ashore. the island slammed by 168-mile-an-hour winds. >> glass, windows were smashed. >> reporter: the united nations children's agency said half the population was affected by cyclone pam. more than 100,000 people including 54,000 children. there are unconfirmed reports of remote villages wiped out and dozens dead. >> the wind was howling through my bedroom. my bed is against the door. >> reporter: unicef alice clemmons -- >> i'm just holding on for dear life here. all i can do during this is think about people who have absolutely no shelter. this is going to be a horrific humanitarian disaster. we need your help. >> reporter: the president braced for the worst, is already asking other countries for aid.

>> i'm speaking with you today with a heart that is so heavy. >> reporter: this image from nasa was taken just before the category 5 storm reached the capital. the pacific island nation was a vulnerable target, with homes made of wood and tin and few places strong enough to survive the storm. with power out and phone lines down the full extent of the damage is not yet clear. the relief agencies are preparing for a major rescue operation. nbc news, london. thousands of people have been evacuated in chile, due to an out-of-control forest fire. residents scrambled to collect their belongings as the blaze spread. 4,500 people have been evacuated from the area. in this country, for many this week's rising temperatures have been a welcome relief but thanks to all that record cold and snow the warmer weather has also caused a major problem --

flooding. here'ses in's stephanie gosk. >> reporter: what happens when you take all that ice and then add all this rain. rivers can't handle the pressure. in vermillion ohio the water is spilling over the banks and it keeps rising. the high waters closing roads and invading homes. >> it came inside my house, about three feet in my house, destroyed everything. >> reporter: the peak is expected tomorrow morning when the river could reach six feet above flood stage. >> i'm terrified. yeah i am pretty scared. >> reporter: all along major rivers in the eastern third of the u.s. from upstate new york to louisiana, there are flood alerts. the region experienced record-breaking cold, and now must deal with potentially dangerous thaw. >> we haven't seen things this bad in a very long time. >> reporter: river ice can be a formidable enemy, as the temperatures warm ice breaks up and large chunks can easily create jams. the water has no place to go but up over and over its banks. ice on the move can be destructive.

>> the biggest concerns are for the businesses and the homes directly along the ohio river. >> reporter: so far this year ohio is feeling the brunt of the thaw. the bitter cold may be over but the winter woes won't let go. stephanie gosk nbc news new york. the 2016 presidential race hasn't even started yet, but two of the country's top potential candidates are engaged in a political showdown. as jeb bush continues to hit hillary clinton for her use of personal e-mail while secretary of state, he's finding himself at the center of a similar controversy. nbc news white house correspondent kristen welker has the latest. >> reporter: jeb bush making his first 2016 foray to new hampshire. he found himself quickly on defense. >> we complied with the law. >> reporter: having to explain using a personal e-mail account when he was florida's governor after he criticized hillary clinton for using her personal e-mail when she was secretary of state. >> we've now made all of my e-mails long before mrs. clinton's issues came up we

made them public for you to see. it's totally different. >> reporter: there you new revelations about clinton's e-mails. until recently the department of state had no way of saving senior officials' e-mails, suggesting mrs. clinton's e-mails may have been lost. but clinton insist all of her files have been saved. >> those e-mails would be automatically saved in the state department system to meet record keeping requirements. that indeed is what happened. >> reporter: still, the e-mail flap is a distraction for both potential candidates. >> hillary clinton and jeb bush actually launched their campaign that would by them both substantive things to talk about. >> reporter: the race inside the gop is heating up with other potential gop contenders descending on new hampshire today. wisconsin governor scott walker tried to burnish his conservative credentials, suggesting unlike president obama, he could support sending

american troops to fight isis. >> i'm not proposing to engage full-scale boots op the ground but i'm not taking that off the table. >> reporter: tea party favorite ted cruz and former texas governor rick perry are also paying a visit this weekend. according to independent voters who make new hampshire the first in the nation's primary so critical. walker also rejected criticism that he flip-flopped on key issues like abortion. for example, today walker said he's still pro life. walker also took a swipe at bush saying the party needs a, quote, name from the future to win. a sign that even though the new hampshire primary is about a year away the race is on. carl. >> we're learning in the past few minutes a united regional jet had to make an emergency landing this afternoon at chicago's o'hare airport. despite the incident no injuries were reported. when "nightly news" continues on this saturday why are so many homes in colorado suddenly exploding.

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a different kind of marijuana boom is hitting colorado. home explosions. ever since the sale of recreational pot became legal last year authorities have been dealing with blasts caused by the production of hash oil. a new and dangerous effort to produce a more potent form of pot. our report tonight from nbc's

gabe gutierrez. >> fire in the hole! >> reporter: it's an explosive problem. one that can tear through a home in an instant. captain siegfried cline with the aurora fire department organized this demonstration to show how butane can ignite when amateurs use it to extract hash oil from marijuana plants. a new and dangerous effort to produce a more concentrated form of pot. at home. >> and that's the attraction. the purity. it's got a more potent high from it. >> reporter: windows blown out, kitchens ripped apart. in 2013 colorado saw just 12 of these explosions. but last year that number jumped to 32. dozens of people have been hospitalized. amazingly, no one has died. >> that goes up in a split second. >> very fast. very quick. it's not going to allow people to get out of the area in time. >> reporter: here at the state capital no one would argue that the hash oil extraction isn't

dangerous, but given that colorado voters have legalized marijuana, the question is is it a crime. >> i think some districts believe we can already prosecute people for trying to create hash oil at home. >> reporter: the governor's so-called marijuana czar supports lawmakers who are right now trying to regulate hash oil processing. but some feel this is a civil issue, not a criminal one. >> we voted on it. it's legal. it shouldn't be in the criminal system. >> reporter: paul is charged with arson and manufacturing marijuana, after one of these explosions in denver. he's pleaded not guilty. >> the people were doing this were following colorado law, and accidents do happen. but in this country, an accident does not mean that a crime has necessarily occurred. >> reporter: either way, police and firefighters here are on alert. is this one of then intended

consequences of marijuana legalization exploding houses? >> yeah it is. it's a very dangerous consequence. >> reporter: a consequence no one expected during colorado's marijuana boom. gabe gutierrez, nbc news, denver. when we come back nerd alert. one more reason to love pie today. (woman) the constipation and belly pain feel tight like a vise. how can i ease this pain? (man) when i can't go, it's like rocks piling up. i wish i could find some relief. (announcer) ask your doctor about linzess-- a once-daily capsule for adults with ibs with constipation or chronic idiopathic constipation. linzess is thought to help calm pain-sensing nerves and accelerate bowel movements. it helps you proactively manage your symptoms. do not give linzess to children under 6, and it should not be given to children 6 to 17. it may harm them. don't take linzess if you have a bowel blockage. get immediate help if you develop

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how's this for a birthday

celebration. great-grand mother georgina turned 100 this week and celebrated by jumping out of a perfectly good airplane. this is the third sky dive for the south african native. she completed her first jump at the tender age of 92. a bird's stunning flight from the world's tallest building was captured on video today, thanks to a small camera placed on the eagle's back. the bird's-eye view recorded the flight as the bird flew from the top of the skyscraper in dubai to his trainer standing on the ground 2,700 feet below. math lovers and foodies alook have a reason to celebrate today. march 14th, otherwise known as pi today. it has a special significance this year. kevin tibbles has more on what all the fuss is about. >> r theory of smellatith we've determined who is your mama's pie shop in chicago is the perfect way to celebrate. yes, folks, it's pie day.

>> lots of offices do big pie day parties, like 15 pies 17 pie orders. >> reporter: but pie day is not named for the treat's concocted here. it's for the mathematical delight, pi spelled simply p-i, or this greek letter and its kept number crunchers munching for mill enya. take any circle no matter what size, and divide the length around it by the length across it and you always end up with the same number. 3.1415 and on and on for infinity. pretty cool says university of chicago mathematician amy wilkinson. >> what we would call fundamental constant. it comes up in everything you do in mathematics. >> you can't get away from pi. >> you cannot escape pi. pi is always there. >> reporter: the massachusetts institute of technology put out this video, telling applicants they could log in on pi day

3/14/15 at 9:26 to see if they were accepted. students count down to the moment of pi. of course here in chicago, what would pi day be without deep at my pie pizza, a slice and a drink today will cost you $3.14, of course. and our facebook friends are sending out all kinds of pie filler to show how they're celebrating. >> pi deserves a day. >> especially if it's pumpkin. >> reporter: so do the math, and have a slice. 3.1415 won't come around again for another 100 years. kevin tibbles, nbc news, chicago. when we come back a swim team making waves in more ways than one.

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we end tonight with a story of a swim team. there are a lot of those, but this one isn't made up of elite athletes and they're accomplishing what many wouldn't dare to try. they're succeeding out of the water, too. here's nbc's almaguer. >> reporter: the swim team the zombie patrol beat the sunrise and the sea lions to the ocean. the waters here a bone-chilling 60 degrees. they faced it head-on three days

a week. this is no ordinary swim and these students will tell you they're no ordinary teens. >> you've got to know mentally that you're going to be able to do this. >> reporter: the 14 students coping with everything from autism to behavioral issues to learning disabilities put all of that behind when they hit the open waters. >> i hadn't been in a bathing suit for the past like i don't know two years. >> reporter: betsy lindbergh who battled a severe eating disorder now has the confidence to do what most would never dare. >> feeling of empowerment. once i never thought i would do this. >> reporter: coming to this cove for over a year now, their rigorous training is paying off. last june the teens swam the waters off alcatraz followed by a relay race that lasted 12 hours off catalina island. the team is just getting started. their biggest challenge is still ahead, a 21-mile relay at the

english channel. with each stroke in every swim lives are changing like 16-year-old laura. >> i remember when i first went to alcatraz i went over to my mom and i just cried of the she was like what's wrong? i was saying i'm just so happy. >> words cannot describe how proud i am of her. she's healthy, she's happy. >> reporter: their strict discipline carries over to the classroom, where the students at arch academy attend year round have to agree to stay off social media, and where no dating is allowed. its founder said it gives struggling students the structure they need to thrive. >> it's really about reaching kids who haven't been able to be reached in other places that they've been. >> reporter: back in the open ocean, the students have proven there's no limit to what they can achieve. >> we did it! >> reporter: winners in the ter, and now in life. miguel almaguer, nbc news, san diego.

that is "nbc nightly news" for this saturday. i'm carl reporting from new york. from all of us here at nbc news, good night.

>> our exclusive interview with the only father figure in gordon's life. hi everybody. welcome to "access hollywood"weekend edition. parent heart broken n.e. motional pain and clearly under the influence of alcohol gordon buried his soul to dr. phil and i watched it unfold and alongside his stepfather jack walker junior. >> my pain is horrible. my look my heart hurts. >> he has said to me many times that he is going to kill himself. and he's tried. >>reporter: wow! quite emotional to watch that. >> it is. very. very. >>reporter: what touches you th