At minus 67 centigrade, the frigid Russian settlement of Verkhoyansk, in north-east Siberia, holds the record for the lowest temperature in the northern hemisphere. "But how do you show that sort of cold?" asks veteran Arctic photographer Bryan Alexander.
The answer is to ask a local to throw a flask of boiling water into the air and shoot the results. "It didn't just cool into cold water," Alexander explains. Rather, the scalding liquid exploded into a spectacular display of instant-freeze ice crystals and sublimated clouds of cold vapour.
For the unacclimated, these sorts of inhospitable conditions could prove deadly, but not for the horse-herding community that lives here – a people whose traditions Alexander documents in his new book Forty Below, published to mark his and his co-author wife Cherry's 40 years of photographing in the Arctic.
"Before I first came to the Arctic in 1971, everything I'd read was about the manned expeditions, and how extreme it was for these explorers," he says. "But for the people here, the cold is not a threat, it's not perceived as the enemy – and I find that addictive."
'Forty Below: Traditional Life in the Arctic' is published by Arctica Publishing, priced £45.67 (arcticapublishing.com)