coming weeks and not worry about a thing. >> we've got the repetoire there. >> what else can we say? we've got 30 second. >> i read a review of the "spider-man." it says it's challenging for one of the worst movies of all time. let's review the weather for the weekend. >> it is movie watching weather. maybe not that one. you are about to see the end of about storm one. and you think the clearing skies means we're getting a break -- no. storm two rolls in midday tomorrow. chance of thunderstorms at times. some of those could be strong as we head into monday. showers. tonight the terrifying house explosion in virginia. one firefighter dead, 13 more people injured horrific scenes of the aftermath. the house reduced to rubble firefighters were already on the scene investigating a gas leak now grieving the loss of one of their own. how the people who live there survived.

nbc news exclusive. andrea mitchell one on one with vice president kamala harris new reaction to the death of a chief putin critic >> we know that putin is responsible. >> as she pushes for more support of both nato and ukraine. >> do we stand with our friends in the face of extreme brutality or not former president trump defiant after that $350 million decision against him, and now launching a sneaker line with golden hightops. the winter blast dumping up to a foot of snow in the northeast. drivers trapped on a highway for hours as the west coast braces for another dangerous atmospheric river. college murder mystery. two people shot in their dorms. a campus on lockdown the killer still on the loose. terrified students desperate for answers. and the emotional high-flying sendoff for this beloved school police officer. this is "nbc nightly news"

with jose diaz-balart. >> good evening. it is every homeowner's nightmare -- a gas leak leading to an explosion. authorities are investigating if that's what happened last night in the virginia suburbs of washington, d.c. this was the scene immediately after the explosion. a house reduced to rubble neighbors nearby hearing a loud explosion and then seeing the aftermath. firefighters were trapped inside the wreckage, other first responders had to pull them out one unfortunately did not survive. and just in now we are getting our first look at the wreckage in daylight. you can see where the house once stood. now investigators trying to determine exactly what happened while mourning one of their own. we begin with priscilla thompson in sterling, virginia. where's kelly? >> reporter: shocking scenes from loudoun county, virginia >> that house is gone. >> reporter: where tonight officials are investigating what led to this massive house

explosion in sterling that they say killed one and injured 13 loudoun county fire and rescue identifying the deceased as 45-year-old firefighter trevor brown, a husband and father of three. >> in a sense we lost -- we lost a family member. we lost one of our own. >> reporter: the 911 calls came in at 7:38 p.m. friday night with residents complaining of a gas odor firefighters arrived on scene to investigate a propane tank leak. within minutes - >> we have a house explosion. significant damage [ sirens ] >> reporter: a nearby resident capturing the moments after the blast occurred leaving a vast debris field down the street >> please help me get out. i'm trapped. please get me out. >> reporter: fire crews worked to recover multiple first responders from the wreckage brown was declared dead on the scene. the two occupants of the home

were evacuated prior to the blast and sustained minor injuries their neighbors still reeling. when did you first realize something was happening last night? >> when i fell off the couch. >> reporter: you fell off the couch? >> i did it was -- it was the aftershock it was so forceful >> what we thought is that somebody went inside my driveway and crashed into my garage that's how it felt boom huge explosion >> reporter: authorities tonight are still trying to figure out what exactly ignited the explosion. is there any risk to others in this community or any other danger >> so no, doesn't appear to be at this time >> priscilla joins us from the site of the explosion. how long do authorities think this investigation may take >> reporter: jose, officials say it could take days or even weeks. the key question -- what ignited the explosion? jose >> priscilla thompson in virginia thank you very much. now to an nbc news exclusive.

our andrea mitchell one on one with vice president harris who is currently on an international trip to reaffirm america's commitment to ukraine and nato the vice president with some tough words for vladimir putin a day after the death of a top russian dissident. >> reporter: tonight alexei navalny's death sparking outrage among his supporters in russia and around the world >> we know that putin is responsible. >> reporter: across russia navalny's grieving supporters laying flowers in his memory and praying, braving a ban on any tributes more than 300 arrested his mother trying to retrieve his body from the morgue and stop russia from hiding evidence of possible murder but she's told his remains are no longer there. his spokeswoman tweeting, "it's obvious they are lying and doing everything they can to avoid handing over the body." >> thank you >> reporter: in an exclusive interview i pressed vice president kamala harris on this question and also who's responsible for navalny's death. is there any indication that

it's not vladimir putin? do we have any evidence >> we will verify it at some point. >> reporter: his spokesperson has said they want the body back, and that the russians are now investigating his body destroying evidence perhaps? >> well, i wouldn't put it past them, but we'll make a determination. >> reporter: the death of putin's most celebrated opposition leader galvanizing world leaders gathered in munich along with ukraine's president volodymyr zelenskyy. >> putin is a threat to all free nations. putin is the monster who invaded ukraine and killed thousands and thousands of people and kidnapped and deported at least tens of thousands of ukrainian children >> reporter: harris meeting with zelenskyy and promising the u.s. will send more weapons. >> we stand with ukraine. we have stood with ukraine since day one. >> i thank you for this, but we need now your unity during such challenging periods for us

>> reporter: with ukraine retreating overnight from a frontline city now decimated by russian attacks -- do you think that ukraine can survive a year, this year on the battlefield without american aid >> ukraine needs our support, and we must give it. >> reporter: tonight zelenskyy telling members of congress from both parties that without more u.s. air defenses ukraine will keep losing ground >> we need to do our part do we stand with our friends in the face of extreme brutality or not? and i say we stand with our friends. >> reporter: do you think that vladimir putin has been emboldened by what donald trump said about nato and about putin? >> i mean, the idea that the former president of the united states would say that he, quote, encourages, encourages a brutal dictator to invade our allies and that the united states of

america would simply stand by and watch -- no previous united states president regardless of their party has bowed down to a russian dictator before and now we are seeing an example of something i just believe that the american people would never support. >> andrea joins us from munich now. on the situation in gaza, today israeli prime minister netanyahu repeated his intention to go into rafah what did the vice president have to say >> reporter: well, that's right, jose harris told me she's concerned about the more than a million people sheltering there. she says the president has not decided to stop arming israel jose >> andrea mitchell in munich, thank you. and a programming note tune in tomorrow to "meet the press" for an interview with a key leader sounding the alarm about the threat from russia former president trump is on the campaign trail

tonight lashing out over yesterday's crushing court ruling fining him hundreds of millions for lying about his real estate empire in a surprising detour from campaigning today, he announced a new sneaker line vaughn hillyard reports. >> reporter: donald trump out of the courthouse and back on the road tonight >> this is a big crowd. >> reporter: appearing at sneaker con in philadelphia. >> we're going to remember the young people, and we're going to remember sneaker con you're sneaker heads, right? >> reporter: less than 24 hours after a new york judge ordered trump and his company to pay more than $350 million in damages for years of fraudulent business practices and lying about the value of his properties, the former president took today to promote a money-making deal, having struck a naming rights agreement for a limited edition sneaker line the most expensive pair in the series selling for $399 >> that's the real deal

[ cheers ] that's the real deal >> reporter: in a surreal scene for a party running for president vowing to appeal the judge's decision that bars mr. trump from running a business in new york for three years. today voters we found in the swing state of michigan had tepid reactions to the fallout from trump's civil business fraud trial. >> i think it will impact him financially but not in the presidential race. >> reporter: those at his rally defending trump. what did you make of the new york judge's decision yesterday? >> i think it's a hoax it's all made up >> reporter: mr. trump's remaining rival for the gop nomination, former south carolina governor nikki haley, in her home state today one week before the primary there. using trump's numerous legal issues to make the case for her candidacy. >> you can't win an election if you're spending more time in court than you are on the campaign trail you can't do it. >> and vaughn is in waterford

township, michigan, where former president trump is campaigning tonight. how is the judge's decision in the civil case impacting the campaign >> reporter: once again the trump campaign is not running from his legal issues and instead taking them head on, including sending multiple fundraising appeals just today in response to that judge's decision yesterday jose >> vaughn hillyard in michigan thank you. dangerous and deadly winter storms are sweeping across the country tonight bringing snow, ice, and the threat of even more floods to the already-saturated west coast george solis reports from new jersey tonight where they got nearly a foot of snow. >> reporter: a fast-moving snowstorm blasting across the northeast today. dumping more than a foot of snow in parts outside allentown, pennsylvania, they're digging out from 14 inches >> i feel so high up because there's just so much snow >> reporter: in new jersey, ten inches dropping down on top of a major snowfall just days ago

backbreaking work. >> yeah. and you know, a lot of sidewalks to clear, my driveway to clear >> reporter: officials warning once the snow melts, it could be even more dangerous. >> be careful because the black ice could still be a threat to us right now >> reporter: the storm first plowed through the midwest claiming at least one life on friday a 19-year-old was killed in a brutal car accident on an icy highway according to the missouri highway state patrol near st. louis, interstate 70 was crippled by slick roads and multiple crashes >> i really didn't want to be stranded >> reporter: michael brown and his family were stranded for four hours, ultimately taking matters into their own hands, driving down an embankment what happened? >> we didn't have any food or water. i just decided to do it and took a chance, and fortunately we made it. >> reporter: all this as the west coast now braces for a new round of wet and dangerous weather, another atmospheric river with potential to create flooding and mudslides expected to slam california over the next few days

>> and george solis joins me from new jersey. george, what do things look like tonight where you are? >> reporter: yeah, the northeast in for a major improvement tomorrow with the sun shining and temperatures expected to be warmer snowmen like this not expected to fare as well. but the risk moving forward this weekend is out west where evacuations have been issued for portions of santa barbara county flooding, high winds, and serious snowfall could also impact millions. jose >> george solis in new jersey thank you. coming up, college murder mystery. two people found dead in a college dorm room. the killer still on the loose. also, could this scan save your life? is it worth thousands of dollars to get a full-body mri?

we are back with a college campus murder mystery after two people were found dead in a colorado dorm room the killer on the loose and students living in fear elwyn lopez has the latest >> reporter: tonight a deepening mystery after the tragic discovery of two people gunned down inside a dorm rocking this tight-knit college campus >> alpine village for gunshot victims -- >> reporter: police swarmed the area friday morning forcing the university of colorado colorado springs into lockdown. >> i'm not sure if the scene is safe - >> reporter: an alert was sent to students urging them to lock

interior doors, turn out the lights, move away from sight, and maintain silence >> it was just disturbing it was quite sad, as well, because we're like family here at uccs. >> reporter: a few hours later the shelter in place was lifted, police saying two people were killed but that it did not appear to be a murder-suicide suggesting a third person was involved >> these deaths are being investigated as a homicide >> reporter: the deaths still shrouded in mystery tonight. authorities not identifying any possible suspects or any known relation to the victims, and also not saying whether those killed were students can you tell us why authorities are tightlipped in cases like these? >> i know it's frustrating for people because they want all the details, but authorities, investigators need to keep some of those details close to themselves because they're trying to not tip off the perpetrator. >> it is our duty to provide the victims of families with support. we will share the

details of what we have learned with them before we release them to the public >> reporter: the school scrapping all weekend activities and offering counseling service for students and staff. tonight the campus eerily quiet and empty as more questions arise. elwyn lopez, nbc news. still ahead, the health trend that can cost thousands. why some healthy people are getting full-body mri scans to search for cancer. are they worth it?

what if there was a test that could detect cancers well before they're life threatening? would you take that test what if i told you it cost more than $1,000? some companies are offering just that with full-body mri scans. but many doctors say it's not a good idea. here's vicky nguyen. >> reporter: andrea schaeffer said she purchased a full-body scan as a birthday gift to herself last year. what prompted you to get this scan >> i'm a 44-year-old woman, and my mom when she was my age had breast cancer. >> reporter: she says the scan found a cancerous brain tumor. two months later she underwent surgery to remove a mass the size of a walnut do you think this scan saved your life? >> yes >> reporter: full-body scans are a growing trend on line, touted by celebrities and influencers like kim kardashian and maria menounos medical groups like the american college of radiology say these

scans are expensive, not covered by insurance, and can result in unnecessary medical tests and procedures the premise is simple -- scan for early detection of cancer and other conditions using radiation-free magnetic resonance imaging or mri. >> we have helped our members find numerous types of cancer >> reporter: emi gal is ceo of ezra his company offers full-body mri using artificial intelligence to reduce screening time and cost a 30-minute scan costs $1,350 >> the report might find really cancer or 500 other diseases >> reporter: can most people handle that much data without becoming overly anxious? >> the vast majority of scans don't require any followup scans. it's the report that essentially gives you peace of mind >> reporter: ezra's scientific adviser says these scans are most effective when patients get them year after year but is it realistic for someone to pay several thousand dollars

every year for a scan like this? >> i think it is if it provides that confidence about health >> reporter: dr. matthew davenport says scans are not recommended by any medical society for healthy, low-risk patients >> if this is a free test, we still wouldn't recommend doing it >> reporter: you think that these health scans end up leading to more medical interventions that could create more harm to the patients >> that is unquestionably going to be the result of this it will result in more testing and more biopsies and procedures and operations >> reporter: his advice, talk to your doctor. andrea plans another scan this year >> you can't put a price on it. this saved my life >> reporter: vicky nguyen, nbc news, new york when we come back, good news about the emotional high-flying sendoff for a dedicated school officer.

there's good news tonight. you know so often the good news doesn't get as much attention as the bad. so every saturday we highlight the many people who spread joy and love these are just some of those stories this week. in arizona, this is the heartfelt reunion between debbie freeman and members of the phoenix fire department last november she collapsed in a local restaurant, going into cardiac arrest now stronger, she credits this team's quick response

with saving her life. debbie and her life partner michael barry forever grateful >> those seconds is what saved her life >> don't make me cry but it doesn't seem like enough, but it was really important that we come and let them know and there was this high-flying retirement surprise for longtime school resource officer troy ensara near st. louis. >> here we go. >> that's troy waving good-bye from a ride donated by local pilot matt lombard after 27 years in law enforcement and 12 years at the school, troy's leaving to pursue his dream of getting a commercial airline pilot's license. >> i'm signing off for the final time >> congratulations, sir. in california, 3-year-old jayla flores has a condition that makes walking really hard without help

look at this breakthrough moment >> she did it! she did it >> she's with her brother joseph when she gets up the stairs all by herself those small steps a proud moment for both jayla and her big brother. >> again again! and this moment is about going above and beyond that's travis goldman and the team from the greenville, south carolina, public works department after they pulled off the impossible -- finding melanie harper's lost anniversary ring among mountains of recycling the guys didn't even think twice about sorting through it all to help a neighbor in need >> just thrilled to have it back on my finger where i think it belongs. >> do you ever think about when you were looking for it what it is that it meant for someone that you didn't know >> if it was somebody that, you know, i loved and had a ring, i'd want somebody to find that ring, too.

>> unbelievable. these are things that just never happen essentially kind of figured that you'd never see that again. >> i was shocked >> their help is a lesson melanie says she will never forget >> it also makes me think to maybe go above and beyond in my daily interactions, what can i do to move forward and spread that kindness that was done to me that's "nbc nightly news" for this saturday. kate snow will be here tomorrow night. i'm jose diaz-balart thank you for the privilege of your time, and good night.

we're tracking rain. we'll bring you the updated timeline. gunfire in a south bay neighborhood. the new details from police. and the push to recall oakland's mayor after nearly a year in office. the kickoff for the group that wants her gone. thanks for joining us. >> we're taking a live look outside san francisco as we're tracking a rainy weekend. >> we're already seeing problems in the north bay. this video from santa rosa, a tree down along 4th street. we could see even more of this over the next couple of days. >> let's get to rob mayeda. what are we expecting? >> right now we're watching two storms. the main event pushing through the area in