Link to newsround

Big freeze continues to grip USA

A man walks in front of the partially frozen American side of the Niagara Falls on during sub-freezing temperatures in Niagara Falls, Ontario.

Parts of America are seeing their coldest winter for decades as snowstorms continue to batter many states. Here a man walks in front of the partially frozen American side of the Niagara Falls during below-freezing temperatures in Ontario.

A partially frozen American Falls is seen lit by lights during sub freezing temperatures in Niagara Falls, Ontario

Here, a partially-frozen American side of Niagara Falls is lit up by coloured lights at night. Near-record low temperatures have closed thousands of schools in America's north east and grounded many flights.

A partially frozen base of Horseshoe Falls is seen on lit by lights during sub freezing temperatures in Niagara Falls, Ontario

These are the Horseshoe Falls at Niagara Falls, which have frozen for the second time in weeks. Over the weekend a powerful winter storm pummelled much of the east coast of the US.

This March 3, 2014 NASA Terra satellite image shows snow cover along with ice covered lakes Superior (top) and Michigan.

The Great Lakes in the north of the country are freezing over too. This satellite image taken by Nasa on March 3, shows the ice covered lakes Superior (top) and Michigan. Researchers say the entire Great Lakes system is 90% iced over: the record is 94.8% back in 1994.

A man walks away from a vehicle after it ran off the icy road

A man walks away from a vehicle after it ran off the icy road in the north eastern coastal state of Delaware. The snow and ice have caused lots of travel problems.

A large snowball fight on The Mall in Washington, DC.

There were opportunities to have a bit of fun too. A large snowball fight broke out on The Mall in America's capital, Washington, DC on Monday.

Greg Novak stands next to the giant 50-foot snowman he's created in Minnesota.

Here's Greg Novak with the giant 50-foot snowman he's created in Minnesota. He says it took him hundreds of hours to build the snowman named Granddaddy, that he hopes will cheer people up if they're feeling fed up with the winter.