By Tarquin Cooper Published: 1:00PM BST 14 Oct 2009  Tarka L'Herpiniere takes the lead in the Patagonian Andes  Katie-Jane Cooper on the ice  Losing a tent has always been the explorer's worst nightmare. Those fabric walls may seem flimsy, but they are quite often the difference between life and death, providing a sanctuary against the harsh elements, a place to cook and get warm.  But this was the stark experience that recently befell 28-year-old Tarka L'Herpiniere and 30-year-old Katie-Jane Cooper in one of the most hostile environments on earth.  They were two-thirds of the way into an epic attempt to cross, unsupported, the world's third largest ice cap in the Patagonian Andes, when the pressure of heavy snowfall – falling at the rate of six inches every hour – caused one of the poles to snap. Released from tension, the sharpened end flew around like a ragdoll, ripping through the tent fabric, wreaking havoc.  "It was horrific," recalled L'Herpiniere, speaking in the Argentinian town of El Calafate just days after the incident. "If you've got your tent and cooker, it doesn't matter how bad the weather is outside. When your tent goes, it really becomes a matter of just surviving."  "I have never, ever heard that kind of fear in his voice when he was giving me directions," Cooper added. "To hear fear creeping into his voice absolutely terrified me."  The 270-mile-long ice cap, in the Andean mountains between Argentina and Chile, has some of the worst weather in the world. In a month on the ice, the pair had seen the sun for just three days. The rest of the time visibility was limited to each other. Howling winds were their daily companion. The tent was essential.  Outside it was gusting at 70mph, too strong to even stand up, let alone fix the problem. All L'Herpiniere and Cooper could do was watch in horror as their tent was torn to shreds.  Forced out into the elements, the pair spent the next five days battling their way off the glacier to a point where they could be picked up. L'Herpiniere required all his experience to make the right decisions to stay alive. That display of survival skills and fortitude has left their fellow explorers in awe.  "It could have gone very wrong," the polar explorer and friend Ben Saunders says. "But Tarka has a ton of experience. He's unflappable, I've never known him to panic. The real story is how they handled it so well. They were at the limits."  For the Anglo-French L'Herpiniere, who gave up professional rugby for exploring, it wasn't anything heroic. "We went into survival mode," he said.  Ignoring the instinct to cut and run, the pair instead forced themselves to rebuild their camp. Using skis and ski poles, they salvaged enough of the tent to make a basic pyramid shelter. It was enough to rest in for six-hour stretches. Sleep was out of the question.  The journey off the ice was every bit as epic as the trek so far, which had seen its death-defying moments. They'd skied up to 10 miles a day carrying 50kg rucksacks when, three weeks in, Cooper collapsed.  "Within moments of me saying I wasn't feeling very well, I had a complete seizure," she recalled. "I was fitting. I had full dilation of the pupils, a nosebleed and was then unconscious. It was terrifying for Tarka as at that moment he didn't know what it was."  A phone call to the doctor diagnosed carbon monoxide poisoning from cooking inside the tent. Cooper quickly recovered in fresh air.  But with the tent gone, the pair faced their biggest challenge – a 1,200-metre descent through a minefield of crevasses hidden by a fresh layer of snow. Then Cooper, once a Pony Club eventing rival of Zara Phillips, suffered snow blindness after damaging her goggles and L'Herpiniere got frostbite in two toes.  It was in these circumstances that L'Herpiniere fought to find a way off the ice. Leading the way, prodding the snow with his ski pole to test the ground, he still fell eight times into crevasses during the dramatic descent. Some slips were innocuous, on other occasions Cooper dropped to the ground, becoming a human anchor to hold him on the rope.  It was the ultimate test of their partnership. Three days later, L'Herpiniere proposed marriage. "I nodded and snatched the ring – I couldn't muster a word," Cooper said.  Having failed to locate a safe way off the ice, the pair were forced to call in a helicopter but, amazingly, the experience hasn't put them off.  "It's so quick for the pain and misery to disappear," Cooper says. "You just forget the bad bits. We haven't been put off at all."  The couple plan to reattempt the feat next year. "But with a different tent," L'Herpiniere adds.
Tarka L'Herpiniere and Katie-Jane Cooper, fresh from the ice fields, recall    the Southern Patagonian expedition they nearly didn't come back from.