Half the world covered in snow.

At first glance it looks like a graphic from a Discovery Channel programme about a distant ice age. But this astonishing picture shows the world as it is today - with half the Northern Hemisphere covered with snow and ice.

The image was released by the National Oceanic And Atmospheric Association (NOAA) on the day half of North America was in the grip of a severe winter storm.

The map was created using multiple satellites from government agencies and the US Air Force.

That Antarctica, the Arctic, Greenland and the frozen wastes of Siberia are covered in white comes as no surprise. But it is the extent to which the line dips down over the Northern Hemisphere that is so remarkable about the image.

The shroud of white stretches down from Alaska and sweeps through the Midwest and along to the Eastern seaboard. The bitter cold has reached as far as Texas and northern Mexico where in Ciudad Juarez temperatures today were expected to dip to minus 15C.

In the U.S. tens of millions of people chose to stay at home rather than venture out. In Chicago, 20in of snow fell leading to authorities closing schools for the first time in 12 years. The newspaper for Tulsa, Okalahoma, was unable to publish its print edition for the first time in more than a century.

More here.