welcome to bbc news, a warm welcome to bbc news, broadcasting to viewers in north america and around the globe. my name is mike embley. our top stories: the big freeze hits parts of the us. arctic conditions are sending temperatures down below —30 celsius. the european union insists it won't renegotiate britain's brexit deal, despite the vote in parliament seeking changes to the so—called irish border "backstop". more street protests in venezuela as president maduro refuses new elections but says he will talk to the opposition. tensions remain high in zimbabwe where the army continues its crackdown against protestors. and millions of migrants are making their way in record numbers, from north america to mexico. millions in the american midwest are experiencing a blast

of arctic air so ferocious they're being warned they risk frostbite if they stay outside for more than 10 minutes. at least 7 people have died in several states as a result of the so—called polar vortex. research suggests a warming arctic is driving very cold air south from the north pole. neda tawfik reports. a steam fog settles over lake michigan, as the polar vortex grips chicago with the most extreme cold in a generation. temperatures fell to —30 degrees celsius and, with the windchill, it felt like —46 degrees, making it colder than parts of antarctica. you see this on my glasses? this is notjust fog, this is frost. it's ridiculous out here, and it's going to get worse. it's really freezing. it's really bad. yeah, it's dangerous. put layers on, make sure you're covered, and don't stay out too long. the polar vortex has sent arctic air across the midwest, affecting 50 million people.

a state of emergency is in place in illinois, wisconsin and michigan. authorities warn that the exteme temperatures are life—threatening, authorities warn that the extreme temperatures are life—threatening, and thatjust minutes outside can lead to significant frostbite. we just want to make sure that people understand the severity of the weather out there, and that they are prepared. it's notjust the person who is risking it by getting outside. it is other people, that are first responders, who may have to show up on the scene. at least six deaths have been connected to the extreme cold. in several states, warming shelters are open for the homeless and other vulnerable residents. hey, you need gloves! in minneapolis, police even handed out gloves to residents. businesses, schools and government officers have been shut, flights have been grounded and travelled disrupted. at chicago's union station, workers set fire to the rails to prevent them from freezing, using a built—in system that turns the tracks into a giant gas grill. and in grand rapids, michigan,

white—out conditions were blamed for two dozen vehicle crashes. ijust got caught in a giant wreck. the deadly deep freeze has brought life in the midwest to a standstill. it is expected to hover over the region for several more days, and scientists warn that, because of climate change, these exteme weather events could happen more frequently. neda tawfik, bbc news, new york. we will be going live to a suburb in chicago shortly. let's get some of the day's other news: president trump has lashed out at his own intelligence chiefs, contradicting their latest assessments on iran and north korea. the president described their reports as extremely passive and naive, and suggested they go back to school. the president had been infuriated by evidence given to a senate committee on tuesday. saudi arabia says it has ended its anti—corruption drive, launched in 2017, that saw hundreds of princes,

tycoons and business chiefs rounded—up. according to officials, more than $100 billion in assets, including property and cash, has been recouped by the state. more than 200 people have been held, many of them in hotels in riyadh. toxic smog in bangkok has forced more than 400 schools to close for the rest of the week, to protect children from its harmful effects. thailand's capital is experiencing some of its worst—ever air pollution levels and the authorities' efforts to clear the air have so far failed. traffic exhaust, burning crops and pollution from factories are blamed for the haze. facebook users have continued to rise despite a series of data privacy scandals and criticism over its attempt to stem toxic content. fears that the company's scandals could put off advertisers also proved unfounded with annual revenues up 30% on last year. user growth was particularly strong in india, indonesia and the philippines, but flat in north america. the british prime minister has begun her attempt, backed by a vote in parliament, to renegotiate her brexit deal.

reports suggest there's been an "open and frank" discussion with the president of the european council. that's usually code for a stormy exchange of views. theresa may faces stiff resistance from european leaders, who insist the so—called "backstop", to ensure there's no return to a hard irish border, must stay in place when the uk leaves the eu. this from our political editor laura kuenssberg. a different kind of meeting in his diary — the labour leader off to see his biggest rival. the prime minister leaving not to wrangle conservatives, but to talk to him. reporter: will the eu make any changes? tea and biscuits served behind closed doors in her private office in parliament. but, after a0 minutes of talks, did the labour leader and the prime minister find any common ground? serious, exploratory on the issues, and i set out the labour case for a comprehensive customs union with the european union, in order to protectjobs in this country, and trade.

reporter: can we find an alternative to the backstop? looking forward to the day today, thank you. the cabinet has already promised to redraft the arrangements for northern ireland. the backstop will have to change, and the prime minister will be negotiating with our european partners to get the very best deal for britain. ministers will consider if the backstop, that insurance policy against a hard border, could have a time limit, or if the uk could leave when it likes, or that technology could be found to manage the border instead. but, even though she won the vote last night... questions to the prime minister. ..the problem, the prime minister well knows, is that the eu has said no to all that before. the majority in this house voted to maintain the commitment to no hard border between northern ireland and ireland, to leave the european union with a deal, and to set out to the european union what it will take to ensure that this house can support a deal. that is a change to the backstop.

that means there is, at least for now, a different mood here. tory backbenchers more used to tearing each other apart over brexit for once backing her, if she can get brussels to budge. tell the european union there is a majority in this house for that deal, and i would ask my colleagues to give the prime minister space. they're not going to crumble tomorrow. we're going to have to hold our nerve, and we can be successful. remember, the prime minister only narrowly got this place on side, last night, because she made a promise that she would get part of her brexit deal changed. but wanting something to happen and making it happen are very different things. and, as far as the eu's top brass are concerned, at least in public, all 28 countries shook hands on the agreement, including the so—called backstop. so a deal is a deal, for now. the withdrawal agreement remains the best and only deal possible. european union said so in november.

we said so in december. the withdrawal agreement will not be renegotiated. with the so—called backstop to protect the irish border affecting ireland, of course, the most, no surprise ireland is protesting most loudly about making a change. we in ireland are essentially being asked, as is the eu, to replace legal certainty, having negotiated that over two years, around british red lines, and to replace it with the hope of something that has yet to be proven. listening to that, it is hard to imagine there is any mood to give the prime minister what she wants fast. but if there is to be a deal, one side or the other, in the end, will have to give. laura kuenssberg, bbc news, westminster. and if you want to look at a useful guide to help explain brexit and what some of the terms, like backstop mean,

just go to our website bbc.com/news or download the bbc news app. venezuela's president nicolas maduro has dismissed calls for new elections, but says he is prepared to talk to the opposition to try to resolve the political and economic crisis wracking the country. it's been another day of anti—government protests, called by opposition leader, juan guaido, who last week declared himself interim president. 0rla guerin is in caracas for us. a student leader stands alone, pleading for a better venezuela. "it's what we all deserve," he says. "think about that when you go home tonight." the security forces remain impassive. they are likely to decide the future here. and for now, it seems they are standing with president nicolas maduro. but the opposition has its foot soldiers, young activists who feel a renewed sense of hope.

well, the students have brought their protest to the edge of the highway. the opposition here wants to keep up the momentum. it says it wants peaceful demonstrations and peaceful change, but there is a real sense here that this is a critical moment for venezuela and everyone is aware of the risk of more bloodshed. larger protests are planned for saturday. the young activists we met believe their time has come. we were born in a dictatorship. we lived all our lives in a situation that gets every time worse, and this is the year that we feel we actually have an actual backing, international support. everything is colliding, so students are here to support the change in venezuela. the embattled president, nicolas maduro, popped up on state television. and he made sure to bring some friends. the message here — i'm going nowhere. but he said he was willing to talk to the opposition

for the sake of peace. and in a facebook address, a warning for donald trump — hands off our oil. supporters of the president also on the move today, doing a drive—by outside a children's hospital. drowning out a protest by parents of sick children. two sides of the divide on display in caracas. but some were determined to be heard today, like romelo cabrera, a journalism student who had joined the protest on his walking frame. "i'm here for the same reasons as everyone else," he told me. "we feel bad for our country. it's painful to see what's going on. my sister and my cousin had to flee. i want them back, i want everyone to come back to a free venezuela." the students ended their

demonstration with the national anthem. "glory to the brave," it says. "down with the chains." this is a nation poised at a crossroads. 0rla guerin, bbc news, caracas. stay with us on bbc news, still to come: memories of biggin hill aerodrome — a new museum opens its doors to the public to tell the story of the raf aircrews who were based there. the shuttle challenger exploded soon after lift—off. there were seven astronauts on board, one of them a woman school teacher. all of them are believed to have been killed. by the evening, tahrir square, the heart of official cairo, was in the hands of the demonstrators.

they were using the word "revolution". the earthquake singled out buildings and brought them down in seconds. tonight, the search for any survivors has an increasing desperation about it as the hours pass. the new government is firmly in control of the entirely republic of uganda. moscow got its first taste of western fast food as mcdonald's opened their biggest restaurant in pushkin square. but the hundreds of muscovites who queued up today won't find it cheap, with a big mac costing half a day's wages for the average russian. very glad to have you with us on bbc news. the latest headlines: the north—west united states continues to freeze as polar air brings record low temperatures.

the european union insists it won't renegotiate britain's brexit deal, despite the vote in parliament seeking changes to the so—called irish border backstop. more now on our top story. ross fraser is a scottish expat based in arlington heights, a suburb of chicago. very good to talk to you. as a scot you must be used to brutal weather. yes, mostly, buti you must be used to brutal weather. yes, mostly, but i have never experienced anything as brutal as this. it is beyond belief. so tell us this. it is beyond belief. so tell us about, how bad? at the moment it is about —27 air temperature outside, —37, —40 with windchill. it is so called you cannot be navigating outside. some deep breaths and you can fill it in your lungs, exposed skin in a few minutes —— so lungs, exposed skin in a few minutes —— so cold. they are talking about

potentially frostbite. it is absolutely brutal. before you go out how do you prepare and if you have to be out there how do you deal with it? sorry. being out, layers, plenty of layers, make sure there is no exposed skin, hats, scarves, gloves, multiple layers, being out, the advice is to state not out for long. if you start to feel pain in your handsit if you start to feel pain in your hands it means frostbite is imminent. get inside and get yourself warmed up.|j imminent. get inside and get yourself warmed up. i am glad we can still talk to you. i was afraid you had killed over from still talk to you. i was afraid you had killed overfrom the still talk to you. i was afraid you had killed over from the old thing. i gather there is worse to come —— keeled. it has been critical. it has been —50 with the. temperatures tomorrow are supposed to be cold —— with the windchill. it's getting close to freezing point by the weekend and maybe above freezing by the weekend. at the moment it is a

blast of two or three days, but there is respite on the horizon.|j know for many natives of the area it isa know for many natives of the area it is a badge of honour to just brush this off, but there is a serious side. something like 18,000 homeless people in chicago. this is very tricky, deadly possibly if you were sleeping rough. i live in north-west suburbs, so i don't see it every day, but i work in the city, there area day, but i work in the city, there are a lot of homeless people around. tempted to is like as people prepare for, but these temperatures, there area for, but these temperatures, there are a lot of shelters that have been opened, i read today and saw some articles about the city providing homeless shelters, more shelters, asking local churches to open their doors and asking people as a whole to chip in and help fellow citizens. it is good to talk to you. you take care. thank you. thank you. zimbabwe has seen unrest this month and violent suppression, as teachers and other state workers protested at worsening economic conditions. even though the demonstrations ended almost two weeks ago, the bbc has heard testimony

from victims that the army is still using brutality and sexual violence to repress opposition. and the crackdown is expected to continue, as teachers plan a nationwide strike on tuesday. the bbc‘s andrew harding sent this report. a bullet through both legs as he ran away. soldiers shoot me. a broken arm. soldiers they, started beating me up. zimba bwe's security forces on the war path. assaulting these men on the streets of harare. and slowly women are coming forward, too. also scared to be identified. six tell us they have been raped by soldiers. this woman, a young mother of two, told us she believed the intention was to do write the whole neighbourhood. they slapped me. they said they want to have sex with me. after that i was so scared. the security crackdown has continued here long after violent street protests about economic hardship shook zimbabwe.

why is the repression continuing? why is it that it's happening in the middle of the night, where people's homes are being invaded and people are assaulted indiscriminately, like what is happening? and this is unprovoked now? i think surely we can conclude that it's unprovoked. an opposition councillor still in hiding in a township scarred by the violence of the past days. families, even pets, have been assaulted here. what are you afraid of? i'm just being afraid of being kidnapped and disappearing. zimbabwe's opposition leader has ruled out dialogue with government while the army remains on the streets. so what we have is almost a de facto state of emergency. it has not been declared but that is what we are living under. it also shows you that we are back to the old days of dictatorship. the days of tyranny. the days of terror. the days of fear.

a well—placed military source has told us this that crackdown will continue for some time. that the president has sanctioned it and that soldiers have been told to use sticks and batons, not bullets, to crush dissent. the authorities insist they are simply restoring order — that any abuses by the security forces will be investigated. we appeal to the complainants to come forward and also report. then we can also investigate. i think i say it again, there's no—one above the law. but zimba bwe's lawyers, marching through harare, say the law is being flouted by a government intent on scaring people and administering what feels to many here like collective punishment. andrew harding, bbc news, harare. california's bourdy parole has

recommended that should be freed from prison. she was sentenced in 1969. she was 19 at the time —— board of parole. they have twice overruled the board to release. she is now 69. there's been a big rise in the number of monarch butterflies making their annual migration from canada, through the us to mexico. the species hit an all time low in 2014 — sparking a tri—lateral conservation effort to protect the butterfly and its habitat. this year, there's been a 14a% rise in numbers. that's right. indeed, we are very happy to share this news today. it is over six hectares of colonies of overwintering monarchs, the monarchs have flown from canada 2500 miles to get here and spend the winter in mexico. and it's very exciting indeed, because last year we had only 2.4 hectares. as you said, it is a 144% increase. this gives us hope that we might

begin to see a recovery in the population of the eastern migrating population of the monarchs. is always amazing to think of something apparently so delicate doing that kind of migration. why is the monarch butterfly so important? well, as an insect it is a pollinator and, in general, we are seeing a pollinator crisis all over the world. just by itself it is important to be concerned. it is a symbol in conservation as something that unites three countries. it is one of those elements that has promoted collaboration between canada, the united states, and mexico. it also involves very direct work with local communities concerning their forests here in mexico. people in the us and in canada are helping to create or rebuild habitat for the monarchs and it's a very powerful symbol and also because the conservation of the monarch butterfly is beginning to show good results here, as in the united states. so it is encouraging in a context in which all the world needs to be very, very concerned

about our environment. on that point, i think there were a point of local people in mexico stopping illegal logging to help the butterflies. yes, that's right. actually, we have been working in the reserved for 25 years and in the last 14 years we have been working very, very closely with 33 local communities. these are indigenous communities, mostly, that depend on the forest, they live within the biosphere reserve and they have made a very serious commitment to conserve the forest and what we have been doing is helping them find ways to have a sustainable livelihood, getjobs in saving the forests, and, altogether, this effort has led to a very important decrease in illegal logging. several years ago, around ten years ago, we had around 400 hectares of illegal logging a year. at that rate we would not have a forest anymore, a forest reserve. in the last four years we have

literally eliminated is illegal logging. it is good to maintain a good forest and ecosystem for the monarchs to arrive and overwinter here in mexico. biggin hill is one of britain's oldest aerodromes. during the battle of britain — churchill called it his ‘strongest link‘. pilots from the airfield shot down almost 1,500 luftwaffe aircraft. now a new museum has opened its doors to the public — to tell the story of the raf aircrews who were based there. 0ur correspondent duncan kennedy reports. if an air battle can have a front line, the skies over biggin hill was it. remember what we owe to the few...

in 1940, raf pilots held that line against the germans, including the late geoffrey welham. i always felt that if i could see my antagonist, i could out fire him in a spitfire, and that was the big thing. see him, out fly him, fight him. biggin hill's new museum now tells these stories for the first time. like elspeth henderson, who hid under a table during one attack. the bomb bounced off the table itself before exploding. the blast shattered the glass and the windows and the plotting table before setting the building on fire. 0r geoffrey greensmith, who met a wounded german pilot after he was shot down. he had photographs of his two children. one was the same age as me. that upset me. yeah, it still does. but biggin hill wasn'tjust a place about aircraft and bombs. through these letters,

it also became the location for romance and love. lillian simpson and keith 0gilvy stayed sweethearts by writing, even when he became a german prisoner of war. we don't talk in the language of victor and villain, we are sharing people's real human experiences and, hopefully, inspiring our visitors by showcasing the very best of human spirit. biggin hill stood for defiance — an airfield and its people who saved britain. duncan kennedy, bbc news. there is more on all the news any time for you on the bbc news website. and you can get in touch with me and most of the team on twitter — i'm @bbcmikeembley. thanks for watching. hello there.

we've got a potentially disruptive snowy spell of weather on the way. we've got very cold air locked in place and an area of low pressure developing over the atlantic. and it's a perfect breeding ground for a snow event as this moisture moves in across the country, bumps into the cold air — some of us are likely to see some pretty heavy sleet and snow through thursday into friday. so of course some yellow warnings are in force for snow, ice, and also the risk of freezing fog overnight through thursday into friday, it's likely to cause some disruption so stay tuned to bbc local radio and keep tuned to subsequent weather forecasts. but we start this morning on a very cold note, largely clear skies. so many places will be dry. a few wintry showers continue across the north of scotland. we'll also see some freezing fog patches developing. something else to watch out for. we could be looking at temperatures as low as —12 to —15 celsius in some of the scottish glens.

so we could have ice and also risk of freezing fog to start this morning. but, on the plus side, plenty of crisp winter sunshine. now, things start to go downhill across the south—west of england across wales and that weather system arrives, initially bringing rain and turning increasingly to snow across this part of the country. further north and east it should be relatively dry. the sunshine continuing. but it will be a cold day with increasing easterly winds. now this sleet and snow will gather force and become more widespread, pushing northwards and eastwards all the while through thursday evening and overnight. some heavy snow likely across the downs of the south—east into the midlands and certainly across southern and eastern parts of wales. by early friday this is the lying snow, a map. we could be looking at significant accumulations across parts of wales, the south—west, and the south downs, 1—4 centimetres to lower levels. a lot more than that further north. so a significant risk of ice through friday night. rain, sleet, and snow will continue to fall, become lighter and patchier, but it'll still continue to accumulate in places. we'll see wintry showers across the north—east of england and further wintry showers

across the north of scotland. it's going to be a very cold night again, a significant risk of ice. now, our area of low pressure gives to migrate southwards, taking its weather fronts with it. so we'll start to see a slow improvement across the south of the country. but we could still see some rain, sleet, and snow continue for a while throughout friday. this easterly breeze will bring more wintry showers into eastern england and eastern scotland, further wintry showers across the north of scotland. but in between we should see plenty of sunshine around, but that really won't do much for the temperatures. it is going to be another cold day. but stay tuned to the weather forecast. this is bbc news. the headlines: millions in the american midwest are experiencing a blast of arctic air so ferocious they are being warned they risk frostbite if they stay outside for more than ten minutes. at least seven people have died in several states as a result of the polar vortex. many businesses and schools are closed. european union negotiators are insisting they won't reopen britain's brexit deal, despite the vote in the uk's parliament seeking changes to the so—called backstop' they want it in place to ensure there is no

return to a hard irish border when the uk leaves the eu. there are more street protests in venezuela as president maduro continues to refuse new elections, but he says he is willing to sit down to talk to the opposition. president trump has offered his personal support to the opposition leader, juan guaido, in a phone call. now on bbc news, it's time for click. this week: the robots have gone shopping! little orange ones, big blue ones and thin white ones.