US weather: Americans told 'not to breathe deeply or talk' outside as 'deadly' polar vortex causes temperatures to plummet - The Independent

US weather: Americans told 'not to breathe deeply or talk' outside as 'deadly' polar vortex causes temperatures to plummet  The Independent

Parts of America are facing temperatures colder than Antarctica this week, as a cold front sweeps through the upper midwest. US officials are urging residents ...