Announcer this is the cbs overnight news. Welcome to the overnight news. Im elaine quijano. Severe weather killed at least four people this weekend in the south. A wave of storms from texas to canada unleashed floods, devastating wind, lightning, hail, and tornadoes. A week of heavy rain and melting snow has caused flood emergencies in several states, and the threat is expected to continue into the week. Heres tony dokoupil. Reporter scenes of destruction like this motel shredded by a possible tornado in northeastern arkansas guided the central and Southern United States this weekend. As pounding rains, rising rivers and at least eight possible tornadoes ravaged the country. The roof of this home near bowling green, kentucky caved in, killing a 79yearold woman. It was an elderly female which was located in the kitchen part of the house. Reporter the ohio river swelled to nearly three times its normal level in louisville, kentucky and spilled its banks further north, where cincinnati, ohio recorded one of its wettest days on record. Just over the state line in tennessee newlyweds adam and Heather Edwards narrowly survived the massive storm. Were just lucky to be alive. Everything can be replaced. Reporter family members say the couple huddled in a closet as winds toppled trees and hurled vehicles outside. Metal from this barn took off and then the windows busted out. Reporter those deaths in arkansas and kentucky on saturday ended a 284day run without a tornado death in the u. S. , the longest streak on record. But elaine, the good news is experts believe that streak wasnt only luck, predictions might be getting better. Tony, thank you. A newly released memo from democrats on the House Intelligence Committee is shaking up the debate over the russia investigation. Paula reid has the latest from our washington bureau. Reporter House Intelligence Committee democrat adam schiff says his memo vindicates the fbi over allegations it abused its surveillance power to monitor a former Trump Campaign adviser. The fbi had every reason to be concerned that carter page might become an act of a foreign power. Reporter the document was written as a rebuttal to a republican memo released earlier this month. That version accused the fbi of hiding democratic ties to an Opposition Research dossier on trump and russia when seeking a warrant to monitor page. President donald trump hit back at schiff in an interview saturday night. Theyll have a Committee Meeting and hell leak all sorts of information. You know, hes a bad guy. But certainly the memo was a nothing. Reporter the democratic memo claims the fbi did not solely rely on the dossier. According to the new memo, the fbi detailed pages past relationships with russian spies and interaction with russian officials during the 2016 campaign when seeking to obtain and renew the warrant. The author of the republican memo, Committee Chairman devin nunes, doubled down on his claims of politically motivated surveillance during a conservative conference saturday. They are advocating that its okay for the fbi and doj to use political dirt paid for by one campaign and use it against the other campaign. Reporter republicans argue their memo undermines the origins of the russia investigation, but so far its had little impact. Special Counsel Robert Mueller has now secured plea deals with three Trump Associates and just this week he filed dozens of new charges. His first trial, of former Trump Campaign chair paul man anort, will begin in the fall. Elaine . Paula reid. Paula, thank you. It was an emotional sunday at Stoneman Douglas high school as teachers and students returned to the scene of the massacre. Omar villafranca is there. Reporter it was a somber return for the survivors of the deadly mass shooting at Stoneman Douglas. Students and teachers returned to campus, coping with the reality of what happened here. Today governor rick scott called on the Florida Department of Law Enforcement to investigate the initial response to the shooting. Video from school cameras showed that the Armed School Resource officer, Broward Deputy scot peterson, stayed outside the building while the shooting was taking place. Peterson has since resigned. New reports say other deputies didnt enter the school either. Broward county sheriff scott israel addressed the accusations on cnns state of the union. While this killer was inside the school there was only one Law Enforcement person, period, and that was former deputy scot peterson. Reporter nra spokesman dana loesch was on nbc this week and says the gun Group Supports a measure to arm teachers in the classroom. This is something parents and educators are going to have to determine for their schools. Our resources are at their disposal. Reporter but some lawmakers are proposing change. Florida republican congressman brian mast says hed support the idea of raising the age to buy a rifle to 21. The army veteran also says hed support a ban on the ar15, a weapon the former soldier says hes familiar with. It pains me to know that i went out there willing to defend my country, willing to give everything with almost the exact same weapon thats used to go out there and unfortunately kill children here in parkland. And i think theres a very real opportunity here for response. Reporter 74 Florida Republican state lawmakers are asking governor rick scott to remove sheriff israel from his post. But sheriff israel has already said he does not plan to resign. Elaine . Omar, thank you. A 30day ceasefire ordered up this weekend by the u. N. Security council has yet to take hold in syria. There was more fighting sunday but nothing like the intense bombing that killed at least 500 people last week in rebelheld Eastern Ghouta near damascus. A massive refugee crisis that started six months ago continues to grow. Every week hundreds of Rohingya Muslims are still crossing over the border from myanmar, formerly burma, into bangladesh. Since august nearly 700,000 have fled their homes, escaping their brutal military crackdown. Our Digital Network cbsn, investigated the crisis and found social media is being used as a weapon against the rohingya. The new cbsn documentary, weaponizing social media the rohingya crisis, premieres on our streaming network, cbsn, at cbsnews. Com. Coming up, thoughts on gun control from a country that has nearly eliminated shooting even if no one in your home smokes, Secondhand Smoke can be closer than you think. Secondhand smoke from a neighbors apartment can enter your home through air vents, through light fixtures and even through cracks in the walls and the floors. Secondhand smoke is toxic. Especially to children. Protect your family. Visit tobaccofreeca. Com. Announcer this is the cbs overnight news. The parkland massacre has renewed calls to approach gun violence as a Public Health threat, like diseases or car crashes. Over the past two decades the centers for Disease Control and prevention has been restricted from researching the impact of guns on Public Health. Dr. Jon lapook explains the reasons for this and why it could change. Reporter whats been sorely missing in the gun control debate so far has been science. And theres a reason for that. Back in 1993 a cdcfunded study found homicide was three times more likely in homes with guns. That prompted congress to pass legislation in 1996 prohibiting the cdc from doing any research to advocate or promote gun control. The ban had a Chilling Effect on all gunrelated research by the agency. In 2016 nearly 100 medical organizationses urged congress to repeal the legislation. After the orlando nightclub shooting that left 49 people dead, i spoke with former congressman jay dickey, who helped write the law. He told me he had come to regret its effect. Why do you think its wrong now . If we had just kept the Research Dollars going and we had said science is important and we need to get to it, i didnt realize that it was possible to do that. Reporter dickey died last year. But his legislation continues. And last week following the School Shootings in florida congresswoman kathy caster pressed health and Human Services secretary alex azar about the lack of research. Will you be proactive on the Research Initiative . We certainly will. Our centers for Disease Control and prevention, were in the science business and the evidencegenerating business. Reporter this week two republican congressmen, Leonard Lance of new jersey and brian mast of florida, called for restoring cdc funding of research into gun violence. It remains to be seen whether that will snowball into actual repeal of the dickey amendment. Dr. Jon lapook, cbs news, new york. The Winter Olympics ended today with a spectacular ceremony and a possible diplomatic breakthrough. North korea said it is willing to hold talks with the united states. More now from ben tracy in pyeongchang, south korea. Reporter there were fireworks all around the Olympic Stadium during the closing ceremony of the games. But inside it was a picture of peace. Athletes from both koreas marched together, and north koreas delegation was seated just behind ivanka trump. She is here representing the united states, putting on a successful olympic charm offensive. Its very similar to what kim jong un did by sending his younger sister. Shes a softer face. Reporter jean lee is an expert on korean relations. She says the olympics have opened up communication between the two koreas and now potentially with the united states. This is a moment that i hope the South Koreans and the americans recognize. Theres potential to turn things around here. Reporter south korean president moon jaein says the head of north koreas delegation, general kim yong chol, told him north korea has enough willingness to talk to the united states. That would be a sudden aboutface. The u. S. Says the north koreans pulled out of a meeting with Vice President mike pence at the last minute during his visit to south korea two weeks ago. But tensions could get in the way of talks. If planned military exercises are carried out after the games. The Trump Administration also just imposed tough new sanctions on north korea and has provided only vague support for a summit between north and south, an offer made by kim jong un. Does President Trump support the leaders of south korea and north korea getting together at a summit . I think he believes that the dialogue could be could be helpful as dialogue always can be. As long as the message remains the same and the goals remain the same. Reporter of course the goal is to get north korea to give up its nuclear weapons, but previous attempts at sports diplomacy have never led to that and there are no signs that 16 days of sporting events here in pyeongchang have changed kim jong uns mind. Elaine . Ben tracy. Ben, thank you. The cbs overnight news will be right back. Im lucky to get through a shift without a disaster. My bargain detergent couldnt keep up. So, i switched to tide pods. Theyre super concentrated, so i get a better clean. Number one trusted. Number one awarded. Its got to be tide while american Lawmakers Debate gun control, activists in other countries are suggesting measures that have worked where they live. Roxanna saberi visited dunblane, scotland where a mass shooting in 1996 led to big changes. Reporter 22 years since a gunman opened fire at Dunblane Primary School in scotland she was killed. Reporter nick north relives that tragedy. At least 14 have been reporter with each mass shooting in america. You tend to pick up on things that relate to whats happened in your own life. Reporter norths daughter sophie was one of the 16 children killed in dunblane. I just said no more guns. Turns out that i wasnt the only one. Reporter he and other parents pushed politicians to prohibit private handguns. Today britain has some of the strictest gun regulations in the world. If you want to buy a semiautomatic weapon or a handgun at a shop in britain, you cant. Theyre now both banned. And if you want to buy a highend shotgun like one of these, it could take up to six months to clear all the regulations. You can only use manually loaded rifles and shotguns for hunting or hobbies at shooting clubs like this one in london. Member sherman strobul says the police will also visit your home to make sure you store your gun in a safe like this. They may ask your doctor about your mental health. If youve had depression or anything like that, you will not get a firearms license. Ever. Reporter since the 1996 shooting in dunblane britain has experienced only one deadly mass shooting, while the u. S. Has had more than 75. Our response in the uk matched the culture here, which is not one that particularly wants guns. Reporter north now has a message for the florida students calling for more action. Keep reminding people what happened to you. Dont take any notice of people who say, well, youre only teenagers. Do you think these kids can really make a difference . I sincerely hope they can. Reporter in 1996, the same year as the shooting in dunblane, a gunman in australia killed 35 people. That led the country to pass sweeping gun reforms. Germany did the same after School Shootings in 2002 and 2009. In those countries gun violence did not disappear, but deadly Mass Shootings are very rare. R. Still ahead, through Virtual Reality they are changing their minds and helping their hearts. How can you make your hair Even Stronger . Use pantene shampoo together with 3 minute miracle daily conditioner. Their prov formula is like a multivitamin. Making your hair 2x stronger see the difference when you add 3 minute miracle daily conditioner. Hey, sir losealot thou hast the patchy beard of a prepubescent squire thy armor was forged by a feeblefingered peasant woman. Your mom as long as hecklers love to heckle, you can count on geico saving folks money. Boring fifteen minutes could save you fifteen percent or more on car insurance. About 1 in 3 American Adults has high Blood Pressure, which contributes to about 1,000 deaths a day. A doctor in los angeles is tackling the problem through Virtual Reality, giving patients an eyeopening view of the damaging effects of salt inside their bodies. Mireya villarreal looked into this. Reporter for juanita canyon controlling her Blood Pressure has always been a priority. But on this night at Holman Church she was given a virtual look inside herself. Oh, lord. Reporter and was shocked by what she saw. 2,000 milligrams. My god. Reporter when you see all that salt intake, whats that first reaction . Oh, my god. You look at one dish and then you look up and it will tell you how much sodium is in that dish. That brings it to life. Reporter through a Virtual Reality app she was able to see a threedimensional simulation of how salt could core rhode her pumping heart leading to high Blood Pressure and possibly a heart attack. When you actually see whats going on, that opens your eyes. Reporter africanamericans develop high Blood Pressure at a younger age than any other ethnicity with 46 of all black women diagnosed with high Blood Pressure. Dietary guidelines suggest less than 2,300 milligrams of salt a day. But lasagna alone has 2,800 milligrams of salt. A fast food hamburger has 970. Some people would hold the goggles out hee, and we said no, no, it goes right up against your eyes. Reporter dr. Brendan siegel knew Virtual Reality would have the greatest impact on changing behavior. You dont realize how it can just nudge your brain, just take hold of the emotional centers and not let go. Reporter after 12 weeks in cedarssinais medical Centers Program this groups average Blood Pressure dropped seven points, with some peoples systolic Blood Pressure dropping as much as 57 points. I am modifying and i am changing. Reporter now juanita canyon has seen the light. Im just amazed. Reporter about salt. Reporter about salt. Mireya villarreal, cbs Fire Fighting is a very dangerous profession. We have one to two fires a day and when you respond together and you put your lives on the line, you do have to surround yourself with experts. And for us the expert in gas and electric is pg e. We run about 2,500 2,800 fire calls a year and on almost every one of those calls pg e is responding to that call as well. And so when we show up to a fire and pg e shows up