New pictures of Niagara Falls show the attraction looking like a set straight out of Disney film Frozen.
Temperatures in Ontario, Canada, have dropped to -18C, resulting in the Falls looking even more photogenic than they did earlier this month when they first froze over.
Steam can be seen rising from the Falls, as the temperature of the water is warmer than the freezing air, creating the ethereal effect.
Large chunks of ice have formed with the water flowing around them, while surrounding trees and rocks are submerged in snow.
Elsewhere in North America, Chicago has been hit particularly hard by the polar vortex, with video showing Lake Michigan frozen over.
There’s also footage of the Chicago River locked in a deep freeze – a boat can be seen making a path through the ice as it goes.
Average temperatures in Chicago have plunged to -17C, making it the second coldest day on record in the last 150 years.
Locals have been told “not to breathe too deeply outside” due to the extreme cold.
Closer to home, parts of England and Wales are on amber alert after the Met Office warned of potential snow and icy conditions until 9pm on Friday.
Cornwall, North Wales, the North West of England and Western Scotland have already been hit by heavy snow.
