I wasn’t supposed to be on Mount Himlung. As a climber and geoscientist examining climate change, I’d been working with a team near Everest in spring 2014, until a serious avalanche forced us to change our plans. On the border between Tibet and Nepal, Himlung offered an opportunity to continue the research in a similar environment.

With two other scientists, I established a camp by a glacier 6,000m up the mountain. The location felt stable and the weather was fine, but monsoon season was only days away. When one of the team fell ill, I decided to make use of what time we had before the snow came pounding in; while she was escorted down the mountain, I stayed behind to work alone for a couple of days.

The next day, I left my tent to collect snow samples. It should have been only a short stroll. I took a couple of ice axes and my camera, but no headlamp or satellite phone. I was wearing a light jacket over a T-shirt – a parka felt like overkill on that bright, beautiful morning. Suddenly, the snow gave way beneath me and I was plunged into darkness. I was inside the glacier, tumbling into a crevasse. My face smashed against ice as I ricocheted between the frozen walls. I thought I was about to die, but instinctively tried to use an axe to stop my fall. I felt bones snap and my arm was pulled clean out of its socket. I landed hard on my side, crushing my shoulder, the impact forcing all the air out of my lungs.

Fighting for breath, I was shocked by the pain and intense cold. I was no longer falling, but still far from the bottom. My feet dangled over the abyss, while my upper body was supported by a chunk of concrete-hard ice that must have fallen and become wedged. It had simultaneously saved and broken me – with every breath of thin mountain air, I felt the grating of broken ribs.

Apart from my legs, every part of me hurt. I kicked my crampons into the side, not knowing if the block would hold and, gasping with pain, slowly wiggled myself on to it and into a sitting position. Far above, the hole I’d fallen through illuminated about 70ft of ice and a tantalising glimpse of sky. With just one working arm, I knew I couldn’t climb up the way I’d fallen; but nor could I survive a night there as the temperature plunged. I spat blood and wondered if I was bleeding internally. If I was to stand any chance of making it out alive, I had to start at once.

To my right, I could attempt the climb more gradually via a series of ledges made of compacted snow, but it meant inching across hundreds of feet. I’d reach across my body with my left arm to whack in one ice axe, then stretch back for the other and repeat, resting at each ledge. My camera had survived the fall and I used it to film what was happening and talk through my options each time I paused to rest. Talking helped me think and left me with a permanent record of what I was going through. I made slow progress, and at times the challenge seemed overwhelming. At one point, I had to cross 50ft of bare ice over the void – halfway over, I looked down and imagined sliding into the unknowable depths. It was the thought of my mother never learning what had become of me that helped me push through the pain and fear.

Eventually I reached a point where I could climb more vertically. But the walls were loose and brittle, with chunks breaking away as I tested my hold. Twenty feet from the top, I dislodged a slab of ice as big as I was. It bounced off me and I clung on desperately as it crashed into the darkness.

At the top, the crevasse was a narrow crack covered with foot-deep snow, thick enough to have obscured it from above. Now I had to dig my way out of my own grave. That took the last of my strength; free at last, I found I couldn’t stand and had to crawl back to my tent. It had been six hours since I’d fallen and it took two more to cover the 100 yards to the tent, where I called for help on the satellite phone.

It was almost night and I had to wait 18 hours for a helicopter to fly me to hospital in Kathmandu, where I found I’d broken 15 bones, including six ribs and some vertebrae. It’s taken several surgeries to restore me to full working order, but I was determined to carry on with my work, writing a book about my experience and founding a research institute. Like many mountain areas I’ve studied, the Himalayas are being destabilised by climate change and grow more treacherous by the day. Our research has never been more vital; but as I help train the next generation of mountaineering scientists, I will always stress those hidden dangers.

• As told to Chris Broughton

Do you have an experience to share? Email experience@theguardian.com