Polar vortex: A guide to surviving extreme cold

Key Facts

Image source, Reuters Image caption, States of emergency have been declared in a number of US states due to the vortex In the bitter cold winter months, being outside during plunging temperatures can pose a threat to health and safety - and can even be deadly.
Dangerous cold snaps are not uncommon for parts of North America between December and February, affecting millions of people from the Canadian prairies all the way down to the US Midwest and New England.
Image source, EPA Image caption, Goggles and glasses can help keep the temperature around the eyes stable "People don't think about leg cover - walking in jeans in -30 degrees won't get you frostbite, but you might get hypothermia and into trouble quickly," says Mr Dinn, who has over three decades of expedition experience.
Image source, EPA Image caption, Stock your car with supplies to get you going and keep you warm while you call for help "Stay in the car, out of the wind, because wind chill exacerbates the whole process," Mr Dinn says.