Niagara Falls freezes over as polar vortex drops temperatures

It is so cold across North America that the normally rushing falls of the Niagara river have partially frozen. The river is still flowing underneath the ice, which isn’t expected to melt any time soon as temperatures continue to stay below freezing
http://www.theguardian.com/us-news/gallery/2015/feb/20/niagara-falls-frozen-gallery