US east coast braces for heavy snow and bitter cold

The US east coast is bracing for the second major winter storm of the year, with up to 12in (30cm) of snow, blowing wind and bitter cold forecast.
Even before the first flakes had fallen, US government offices in Washington DC and schools in several states were closed pre-emptively.
In New York, snow began falling during the morning commute, and authorities warn of hazardous road conditions.
And more than 2,000 flights have already been cancelled in the US.
The storm comes just two weeks after a weather pattern known as the polar vortex brought heavy snow and record low temperatures to the eastern half of the US.
Winter storm warnings have been declared from West Virginia to Boston, with some of the heaviest accumulations threatened along the coastal cities.
Washington DC is expected to see its heaviest snow fall in three years, and temperatures across the eastern US are expected to be 10 to 25 degrees colder than average Tuesday and Wednesday, according to the US National Weather Service.