on the broadcast tonight, chain reaction. the 911 tapes have been released from the horrible pile-up on the interstate. cars and trucks, fog and smoke. people were driving blind. it left a terrible death toll and a lot of questions. on the attack. he's out to a big lead in florida, but mitt romney isn't letting up on newt gingrich. how much of a turning point could tomorrow's primary be? pressure points. think about the last time you had your blood pressure checked. the chances are they did it wrong. that's what a new study says, while explaining the right way and why it's so important. and making a difference. tonight chelsea clinton with the story of a decorated world war ii p.o.w. who unleashed a secret weapon of his own and his fight to make life better for today's returning veterans.

"nightly news" begins now. captions paid for by nbc-universal television good evening. it was such a bad accident, so severe, that the people we usually associate with airline disasters, investigators from the national transportation safety board are on the scene to investigate this one. people were just driving on the interstate when it happened. suddenly, vehicles driving straight ahead plowed instead into a horrible scene. a massive wreck that left an awful death toll and scarred that section of roadway along with all the lives connected to it. tonight, ten people are dead, 18 people injured. all because drivers were blinded by a brushfire on i-75 in the state of florida. the state in the news these days for politics, where they are mourning these victims tonight. nbc's mark potter starts us off from there this evening.

>> reporter: authorities say heavy smoke from a wildfire mixed with fog led to the horrific string of accidents which about 20 cars and trucks slammed into each other, some catching fire. the pile-ups occurred in the pitch dark around 4:00 a.m. sunday. terrified callers to 911 describe one crash after the other. >> oh, my god. oh, my god. what is going on? >> we are getting help out there okay? >> oh, my goodness. >> how many vehicles have been involved? >> we cannot see, ma'am. this is the third one already. >> reporter: in the entangled mess, rescue workers had to cut many victims from the wreckage. steven camp survived being hit twice and saw another driver get killed. >> it almost looked like a terrorist attack. you could see the pain, uncertainty and despair everybody had on their face. >> reporter: i-75 was shut down all day sunday causing miles-long traffic jams. today firefighters work to extinguish still-burning hot

spots the florida patrol face questions about why the smoky highway was open sunday morning when visibility was so poor. >> it's impossible to see. the haze is and the smoke, it's very thick. >> reporter: the highway had briefly been shut down earlier that morning, but was reopened. >> we made an assessment and came to the conclusion the road was safe to travel. that's when we opened the road up. >> reporter: with the crash investigation, officials are also trying to determine what caused the wildfire, and whether it was arson. mark potter, nbc news, miami. as we mentioned, so much of the other news out of florida has to do with tomorrow's presidential primary. after that big running start for newt gingrich out of south carolina, the polls have now swung mitt romney's way big time, including our own nbc news/marist poll, which shows romney ballooning to a 15-point lead over gingrich.

nbc's chuck todd is here with us to break down the numbers. we want to begin first with the reporting of peter alexander in florida. >> reporter: brian, good evening to you. make no mistake right now, mitt romney is the heavy favorite going into tuesday's primary in florida. the bitter back and forth between romney and newt gingrich continues. today, romney was attacked by gingrich as dishonest and romney mocked gingrich back as desperate. >> what a welcome. oh, my goodness, you guys are amazing. >> reporter: with less than a day to go and the polls showing him with a commanding lead. >> this is fun what a day this is. with a turnout like this, i'm beginning to feel we might win tomorrow, what do you think? >> reporter: a confident mitt romney is dismissing his rival newt gingrich. >> i know, it's sad. he's been flailing around a bit. trying to go after me for one thing or another. you watch and shake your head. it's been painfully revealing to watch. >> reporter: this morning on the "today" show, romney credited his campaign's new strategy to be more aggressive for his

recent surge. >> we were getting wailed on by speaker gingrich and didn't respond well in south carolina. we decided we are going to respond, both the change and tactic, as well as the message have had a real impact here in florida. >> reporter: today gingrich who has been consistently late for campaign events was greeted by much smaller crowds than last week, but he's not backing down. in a state with a large jewish population, gingrich pounced, using this new attack line on romney's record as massachusetts governor. >> he eliminated serving kosher food for elderly jewish residents under medicaid. >> reporter: a cut to medicaid funding was among hundreds the romney campaign says the then-governor made during his state's budget crisis. it was later restored. campaigning with president reagan's son michael, gingrich has been ridiculing romney as a massachusetts moderate for weeks is retooling his argument, blasting romney with a word designed to incite conservatives. >> that party is not going to nominate somebody to is a

pro-abortion, pro-gun control, pro-tax increase. >> reporter: gingrich is getting pummeled on florida's air waves. >> newt has a ton of baggage. >> reporter: with $20 million already spent on largely negative ads, romney and his supporters outpaced the former house speaker and his super pac 4-1. gingrich insists he'll stay in this race through the convention, embracing the role of underdog if he continues to target the media. >> as your nominee, i will not accept debates in the fall in which the reporters are the moderators, because you don't need to have a second obama person on the debate. >> reporter: for their part, ron paul and rick santorum are spending their time and energy elsewhere. santorum is campaigning in minnesota after taking time off the trail to be with his 3-year-old daughter bella who is hospitalized with pneumonia. >> peter alexander starting off our political coverage in florida tonight. as we mentioned, our political director and chief white house correspondent chuck todd paying a rare visit to the mothership tonight.

first of all about newt gingrich, we are out of the moderating business, i guess. >> apparently. >> he kept telling reporters all weekend, look at the national polls where i'm leading. while that may be true, these numbers are moving in florida. >> reporter: they are. because florida is the one state where there are $16 million of negative ads against newt gingrich, you don't have that in the other 49 states. that is benefitting newt gingrich a little bit. what is interesting about this lead from mitt romney and why it seems so solid going into tomorrow, we learned among folks who voted. 1/3 of floridians voted. he leads almost 2-1, 49-27. the other argument you're going to hear newt gingrich make, the conservative vote is divided. we took second choice rick santorum voters, and assigned them to who their second choice is. they broke evenly, slight advantage mitt romney, 49-33 it tells you a little bit that some of the value voters for santorum are turned off by newt gingrich's personal history.

>> i heard gingrich all weekend saying this will be wild, woolly and we are in it all what it to the fall, which he is free to say. what is the reality? >> nobody says they are going to get out. that's number one. number two, february will be a cold, cruel month. it may be short, but it's going to feel like an eternity for him. there's only four caucuses, two primaries very late. no debate for three weeks. newt gingrich lived on this media and now he is relying on some guy in las vegas to keep funding his campaign. at some point he may run out of patience and not write any more checks. >> always good to see you. nice to have you here with us in new york. chuck todd. we turn to news from overseas in syria. the violence has gone from bad to worse. the regime of president assad is set on crushing the anti-government protests that have been going on since last march. ayman mohyeldin is with us

tonight. good evening. >> reporter: good evening, brian. more than 200 people killed in the past five days in fighting across the entire country. it's all about the capital. the government says it repelled an attack by insurgents there and it is firmly under its control. the situation is so dangerous that the arab league suspended operations. this as the united nations convenes on tuesday to discuss a resolution that calls on the president to step down from power immediately. >> you're in cairo. give as report on the situation there. >> reporter: a handful of americans that work for ngos here have taken refuge at the american embassy. the white house says they are not in imminent danger, but there is no real reason why they've gone to the embassy. they are being investigated for receiving money abroad and channelling it to political parties here, which would be a crime under egyptian law. the real test will be if the americans are charged with any crimes, would the u.s. embassy hand them over to egyptian authorities.

>> aman mohyeldin from cairo tonight, thanks. a verdict has been reached in a murder case that's gotten a lot of attention because it involved so-called honor killings of family members by family members. in this case an afghan family living in canada. it is a culture clash getting a lot of attention to our north. nbc's kevin tibbles has the story. >> reporter: three teenage sisters murdered because of how they wanted to live their lives. dress like westerners, use the internet, meet boys. also killed, their father's first wife. by a strict religious family that felt it had been disgraced. >> four strong, vivacious and freedom-loving women were murdered by their family. >> reporter: convicted of the crime, the girls' father, mother and brother, immigrants from afghanistan. in 2009, the women were drowned and their bodies placed in a car that was then pushed onto a canal to look like an accident. they may call it honor killing,

but delivering the guilty verdict, the canadian judge called it a sick notion of honor that has absolutely no place in any civilized society. 59-year-old mohammed shafia came to canada in 2007. the court was told how he ruled his home with a rod of iron. and that eldest daughter was even forbidden to attend school because she had a boyfriend. the young woman had texted the boy saying, "be aware of my bro." it is impossible to know how many honor killings take place in north america, experts say, because they are often mistaken for domestic violence or disguised as accidents. >> they are associated with patriarchal cultures, where men see themselves as the owners of women. >> reporter: it took a jury 15 hours to convict all three of

first degree murder, which in canada carries an automatic sentence of life in prison. kevin tibbles, nbc news, canada. next here, turning medical practice on its ear bit. now there is a new way we should all be getting our blood pressure measured. chelsea clinton explains how a decorated american war hero and the helpers he has recruited here are making a big difference.

as we mentioned earlier, the health news has to do with a basic staple of the doctor's office, getting your blood pressure checked. if your last time at the doctor they only measured it on one arm, well, new research says

they're doing it wrong. further, they say, doing it right could reveal a big health risk. our report from our chief medical editor dr. nancy snyderman. >> reporter: doctors who measure blood pressure in only one arm may be missing critical information about their patient's heart health. a new study published in the journal "the lancet" shows the differences in blood pressure readings between both arms could point to underlying health risks. if the systolic pressure, the top number in a reading which measures the pressure in the artery where the heart beats, differs by 15 points in each arm, this study shows that a person is at 2.5 times higher risk of peripheral vascular disease, meaning blood vessels in the hands and feet are more likely to become blocked and could lead to severe measures like amputation. risk of stroke is 1.6 times higher. risk from death of heart attack is 70% higher. some risk factors for

hypertension are age, genetics, race and obesity. the important thing to remember that your doctor should take blood pressure in each arm. if it's high in one arm, have that blood pressure repeated because some people develop something we call white coat hypertension. they go to their doctors, they're nervous, blood pressure goes up and settles down after a short time. brian, if that's not you and your blood pressure stays up, that's the time you go on and have further tests. it's amazing how many people have falsely elevated blood pressure and don't know it. >> that's the effect you doctors have on the rest of us. >> it's that white coat. >> thanks as always. the new research on what women do better than men. if you don't agree, take it up with the british who did the research.

depending where you live there's already a name for what we are experiencing this winter.

it's called juneuary. temperatures today and tomorrow much closer to what they are in june than they should be in the dead of winter. thus, the newspaper headlines around the nation blaring about winter's virtual cancellation. events called off for lack of snow, ice and cold. with us tonight from weather channel headquarters, our friend meteorologist jim cantore. jim, there is a chance it just never moves in to stay, winter does? >> i think we are going to get winter. february and march, big months for storms. it's not over yet. let's talk about what we had though. this is amazing well. when you look at 9/10 of the country, we have had above normal temperatures. the scale to the top above average. that is above average. we look into february. more of that to the south. this may not bode well for our severe weather potential. we already had 74 tornados this month, third all time. today, 50 plus record highs right in this region here. we will have another slew tomorrow.

i bet they wish the super bowl was in dallas. 72 coming up. it looks like this area will finally cool off by the time we start early next week. some of the extended models do suggest we do cool off starting next week, and possibly a big chill coming toward the middle of february. we're going to have to wait and see. they haven't lasted that long. >> we'll pay for all these stories we keep doing. jim cantore from the weather channel, thanks as always. to be fair, some folks are having a good old-fashioned winter like parts of alaska where the temperature in fairbanks plunged to 49 below zero over the weekend. memorial services were held on friday for john baker, a recipient of the medal of honor. he grew up in iowa and served in vietnam in 1966 and witnessed what was later called something close to hell. his company came up against an overwhelming north vietnamese force. the men who lived to tell it about it survived thanks to john baker. he saved eight of his comrades

and single-handedly destroyed six machine gun nests and killed ten enemy soldiers. president johnson placed the medal around his neck a year later. with the death of john daker jr, there are just 83 living recipients. news from hollywood or closer to london that shirley maclaine is joining the cast of "downton abbey." the british drama with a hot following here in the u.s. in season three, she will play the mother of lady grantham played by elizabeth mcgovern. the producers say maggie smith's character is about to get, quote, a wonderful combatant. lots of heated but cordial discussion in our newsroom today over this next item. a study from the u.k. that says women are better at parking than men. they studied surveillance film and watched how people parked. they say while it takes women longer on average than men to park, women are also better at finding empty spots. this is tough to take for a lot of people. i would remind you, this is a

british study. they drive on the wrong side of the road to begin with and your results may vary. up next here tonight after a break, loving helpers for wounded warriors. chelsea clinton tells us about want one making a big difference.

>> an up scale and quiet suburb rocked by violence.

a tech strategy for detecting gas leaks. construction crews, are. the home front. consider this, over 40,000 of our returning vets have been injured in iraq and afghanistan. as we hear from our special correspondent chelsea clinton, a decorated world war ii veteran, a former p.o.w., is answering the call to help ease the way for young vets who have already given so much. >> this is the uniforms we wore. >> reporter: irwin stovroff has an impressive collection of world war ii mementos. >> i was given the air medal, i did get the purple heart. this is a picture of my plane being shot down. >> reporter: the world war ii hero was on his 35th bombing mission over nazi-occupied france when his plane crashed behind enemy lines. >> they captured me immediately. this was one time i did not think i was going to make it. >> reporter: irwin quickly threw

away his dog tags which identified him as jewish and survived a year in a german p.o.w. camp. now 70 years later, the 89-year-old decorated hero is on a different mission. irwin raised $3 million to supply service dogs to wounded soldiers, including the newly wounded returning from iraq and afghanistan. he began his group "vets helping heroes," after learning there is no government program giving soldiers canine help. retired lieutenant colonel kathy champion, going blind from a mysterious virus contracted in iraq. >> i became a hermit of my own house. i quit school and quit my job. >> reporter: irwin raised money to give kathy her angel. >> she granted me back the life i felt was taken away from me. >> reporter: training these exceptional canines can cost as much as $70,000 per dog and takes 18 months beginning in the puppy stage.

this may look like any other love labrador, but he is so much more than that. he is a working therapy dog, helping service men and women recover from the wounds of war. irwin sponsored brute for the west palm beach v.a. medical center. >> when i first seen him, i fell in love with him. >> reporter: three tours left this master sergeant with debilitating ptsd. >> i was sure i would come home and he would have killed himself. >> reporter: then he got larry and life dramatically improved. irwin stovroff is a true hero. >> you can dwell on all the horrible things that happened to you, or you can turn it around and say, i survived, life is good and let me see what i can do for others. >> reporter: that is the choice irwin stovroff, war hero, advocate for wounded warriors has made. chelsea clinton, nbc news, boca raton, florida. that's our broadcast on a monday night as we begin a new week. thank you for being here with us. i'm brian williams. don't forget "rock center" at 10:00, 9:00 central. our last monday night appearance

before we move to wednesday nights. we have a terrific broadcast planned for tonight. of course, we hope to see you back here tomorrow evening. good night. -- captions by vitac -- www.vitac.com >> good evening. thanks for joining us on this monday, i'm raj mathai. >> i'm jessica aguirre. we begin with the san bruno explosion. who is to blamend how new technology could help avoid a disaster like that in the future. >> congresswoman jackie spears has been a vocal watchdog. she is urging governor brown to reverse a decision by the puc president to appoint himself to lead the