New Yorkers warned of frostbite risk as temperatures plunge

National Weather Service says to make sure all exposed skin is protected' as city's temperatures as low as 15F to 20F on Friday

Plunging temperatures gripped New York on Friday, with the US National Weather Service warning that people in the city risked getting frostbite if they ventured outdoors unprotected.

If people did need to be outside, the weather service advised to wear gloves and hats. It added in a warning bulletin that frostbite can occur in a short amount of time, so dress in layers and make sure all exposed skin is protected".