The Northern Lights glow green in a spectacular light show above a field of trees frozen solid with snow. (Photo by Jaak Sarv/Solent News & Photo Agency)

Bison along the Bitterroot Valley's Eastside Highway north of Stevensville, Montana, are covered in snow following a blizzard on November 23, 2010. (Photo by Perry Backus/The Missoulian)

A four-month-old snow fox cub named “Vesna” (“Spring”) leaps next to a Zoo employee at the Royev Ruchey Zoo in Krasnoyarsk, Russia, on August 6, 2013. (Photo by Ilya Naymushin/Reuters)

A woman holding an umbrella walks past the sculpture by Chinese artist Yue Minjun beside a road during a snow in Beijing, China, November 22, 2015. (Photo by Jason Lee/Reuters)

Swedish brown bears “Fred” and “Frode” play in the snow on January 30, 2014 at the Natur- und Umweltpark (NUP) animal park in Guestrow, northeastern Germany. Despite of icy temperatures, the bear brothers took a break from their winter rest. (Photo by Bernd Wuestneck/AFP Photo/DPA)

A statue of a man sleepwalking in his underpants is surrounded by snow on the campus of Wellesley College, in Wellesley, Mass., Wednesday, February 5, 2014. The sculpture entitled “Sleepwalker” is part of an exhibit by sculptor Tony Matelli at the college's Davis Museum. (Photo by Steven Senne/AP Photo)

Tobias Mueller of Germany falls as Johannes Aujesky of Austria competes in the Men's Ski Cross of Audi FIS Cross World Cup 2022 at Genting snow park on November 27, 2021 in Zhangjiakou, China. (Photo by Lintao Zhang/Getty Images)

Cooler temperatures begin this week as a polar vortex brings much colder conditions with the chance of snow for Snowdonia, Ogwen Valley, North Wales on 22nd October 2018. The Ogwen Valley and Tryfan Mountain looking splendid in the Autumn sunrise. (Photo by DGDImages/Alamy Live News)