Looking out from the jagged headland at Nazaré in Portugal, the Atlantic Ocean below looks tranquil. Baby waves – or so they seem from above – peel left across the town’s northern beach and there’s barely a sign that this stretch of water is considered one of the most monstrous surf spots in the world.

“It’s impossible to visualise it on a day like today when it’s beautiful and sunny but sometimes it gets big out there and sometimes it gets to the next level, beyond the realms ...” says the surfer Andrew Cotton, tapering off as he considers how best to describe the 60ft wave that flattened him exactly a year ago. “It’s like moving mountains,” he adds.

“It’s disorganised, it’s really tricky to surf, there are peaks everywhere, you get these crazy, crazy teepees with loads of energy, and when the waves break right in front of the lighthouse it’s like woah! Without doubt it’s the riskiest spot in the world to surf.”

Cotton knows first-hand about the risks at Nazaré, where a deep offshore canyon funnels the ocean towards the headland and, during certain winter swells, creates waves up to seven storeys high.

Last November, the 36-year-old Devon surfer was hit on the head by a mammoth wave before being spat 20ft into the air, the momentum eventually slamming him down onto the surface of the ocean with such force that it broke his back.

It was dubbed a “liquid catapult into space” by the World Surf League big wave awards. Cotton remembers it all with eerie detail.

Play Video 0:38 Giant wave slams into British surfer Andrew Cotton causing huge wipeout – video

“When I was checking the swell that morning I was seeing giant, perfect lefts,” he says. “I mind-surfed them and I knew exactly what I wanted from the day: I wanted to be in a 60ft barrel. Getting barrelled at three feet is amazing but getting barrelled at 60ft, that’s the dream.

“It was probably my fourth wave of the day and I was like, ‘this is it, I’m going to send it’, but it went from being the best wave I’d ever seen to being possibly the worst. Suddenly I knew the lip wasn’t going to throw out as far as I expected. I could see it feathering above me so I hit the eject button and jumped off.

It was like jumping off the roof of a building on to concrete

“I never jump off my board,” he stresses, the panic recounted in his voice, “but instincts just took over”. The moments that followed were amongst the strangest of his surfing career.

“I’ve fallen off my board a lot in the last 30 years and this time was weird, like nothing else,” he says. “I was having this weightless feeling and I thought maybe I was in the centre of the wave. I thought to myself ‘maybe I could’ve ridden this out’. And then bang! I landed so hard. When that impact happened I was like ‘I’m done’.”

Was it painful? “Umm, yeah,” he says with bewilderment, as if the feeling was almost beyond register. “It was like jumping off the top of a building on to concrete.”

Cotton was swept under by the ensuing white water and took a second, huge wave on the head before being rescued by his tow-surf partner, Hugo Vau. The pair eventually made it back to the beach, where Vau lost control of the jetski and spilled Cotton onto the sand, adding injury to injury. Needless to say, Cotton won the WSL Wipeout of the Year award.

Having suffered an L2 vertebrae compression fracture, he was initially unable to walk. “At first I was on pain killers and I was like ‘it’s not that bad’,” he recalls. “But after a few days they put a body brace on me to see if I could stand up. I couldn’t even put my feet off the bed. Garrett (McNamara) and Hugo were there and I could see on their faces I’d really fucked up.”

Facebook Twitter Pinterest Cotton checks and prepares his kit at Red Bull’s facility in an old shipping yard in Nazaré. Photograph: Jonny Weeks/The Guardian

It has taken 12 months of intensive rehabilitation for Cotton to fully recover. As he wanders around the shipping hanger in Nazaré where Red Bull athletes keep their kit – where photos of past triumphs and remnants of broken boards decorate the walls – he’s feeling grateful to be back on his feet, back in town, back in the water.

He checks his inflatable life vest and CO2 canisters, prepares the first aid kit which includes military-grade tourniquet dressings, and speaks of a mental comeback as much as a physical one.

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“Some days you go on internet binges looking at waves and all your mates having fun and you’re like, will I ever do that again?” he says. “I don’t think you know how much a wipeout like that changes you until you come back.

“It would have been really easy to say ‘forget it’. I’ve got a family, I’m a qualified plumber, I’ve got other stuff going on in my life. Plumbing can get pretty exciting if you’ve got a leak going on!

“But I really, truly love big wave surfing. Some other people just want a picture [of themselves on a big wave] but I want this.”

Facebook Twitter Pinterest Cotton puts on his protective under-armour and wetsuit as he prepares for a paddle-surf in relatively tranquil conditions at Nazaré. Photograph: Jonny Weeks/The Guardian

Last week, in the first significant swell of the season, Cotton surfed waves that were around 40ft high. He suffered another wipeout, this time snapping his board in two instead of his back. That experience fortified his belief that he’s ready to scale Nazaré’s moving mountains again.

“Of course there was fear when I first came back here,” he says. “I was nervous, shaking a little bit with the adrenalin, but I said to myself it’s a long winter, just build your way back slowly.”

Over the coming months he hopes to set new benchmarks while “drawing exciting, critical lines”. And having towed McNamara into a then world record wave at Nazaré in 2011 – the moment when Nazaré first caught global attention – Cotton is determined to add his own record to his ignominious wipeout award.

On reflection, he muses: “Sometimes you have to endure the worst situation to get to experience the best.”

• To find out more about Andrew Cotton, visit Redbull.com