Incredible pictures show Niagara Falls partially frozen as chilly temperatures continue to bring snow and ice across the US-Canada border.
Similar images emerged last year when the falls, which usually see the passage of 567,811 litres per second, partially froze twice in a few weeks as temperatures fell to a record-breaking low.
Pictures taken this year show some parts of the falls and surrounding areas covered in sheets of ice.
Temperatures dropped to -14 on Tuesday, while wind chills on Wednesday dipped to as low as -25F, WIVB.com reports.
The Weather Prediction Centre is warning of a "historic cold" throughout eastern US on Friday, when the first polar vortex of the season is due to arrive.
A forecast on its website advised: "Get ready for an even more impressive surge of arctic air later this week as another cold front drops south from Canada.
"There are indications that this could be some of the coldest weather since the mid-1990s for some parts of the Southeast US, Mid-Atlantic, and central Appalachians.
"An eddy of the polar vortex will add to the potency of the surface cold front, thus creating a deep layer of bitterly cold air."
A polar vortex is a rotating pool of cold, dense air held in place by strong winds.
One visitor to the falls described the scene as wonderful, saying: “It’s like nature is bigger than us.”
Another visitor added: “I’m feeling like I’m losing my nose right now.”
Michelle Blackley, the communications and community relations manager for the falls, told USA Today: "The attention the falls is receiving is bringing a crowd to view them in their majestic, winter splendor."
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