Nepal quake on Everest: BBC man's lucky escape
Mount Everest is a dangerous place, and the Khumbu Icefall is one of the most dangerous parts of the climb. At 06:00 local time on Saturday, we were scrambling through its living, moving blocks of ice.
Crossing the icefall is one of the most technical parts of the climb to the roof of the world. It is an impenetrable wall of beauty and death. Ladders bridge huge crevasses hundreds of metres deep and fresh blue ice tumbles in the night, sometimes cutting the safety lines.
Every morning a team of climbers, known as the ice-doctors, crawl through the ice to check the route through it still exists.
On Saturday my team climbed the final vertical ladder by 11:30 in the morning, while the other team remained behind on the ice.
We'd reached 6,000m (19,700 ft), where the air is thin and the breathing rate doubles. We trudged from step to laborious step. Reaching Camp 1, you can barely stand, let alone react to danger.
'Prepare to run'
I had just stashed my bag safely in my tent when the glacier suddenly came to life, shifting beneath me. The movement was so violent it knocked many of us off balance. It felt like the giant ice flow was sliding off the mountain, pushed by a supernatural force.
Visibility was down to less than 5m (16ft). Above us we had three of the world's tallest mountains, Nuptse, Lhotse and the western shoulder of Everest.
On all three sides came a deep, ominous crashing sound, like the noise of the balls dropping under a pool table but a million times louder.
Huge lumps of ice, called seracs, hang from the sides of mountains. High above us we could hear, but not see, that these had broken off.
Camp 1 has been wiped off the side of Everest on a number of occasions. Its location, at the top of the Khumbu icefall, makes a quick retreat impossible.
I was completely physically exhausted by my climb through the ice, mentally unable to move anywhere with the air so thin. My guide Rob Casserley, a doctor who has reached the summit of Everest eight times, was shouting for us to "keep calm and prepare to run".
The visibility fell to zero. A wall of powder snow and a roaring wind struck us with such force it knocked the lenses clean out of a teammate's glasses.
I fumbled inside my tent and waited for the huge blocks of ice, which would surely kill us. We were powerless. There was nowhere to go, nowhere to hide. By a miracle, the ice never struck us. Later I wished I'd grabbed my camera at that moment.
The earthquake lasted 40 seconds, then the rumble of the avalanches began. We waited. The storm of powder snow lasted three minutes. I have never been so scared, so utterly petrified, so convinced that death was inevitable.
'Basecamp has been destroyed'
When it stopped, our team stood aghast. Our radio still worked and we received a call from our expedition leader at Base Camp, trying to find out if we were still alive. It was then we learned that Base Camp had been largely destroyed. Our safe haven, where we would return for rest and recuperation, had gone. Worse, we heard that three of the local members of our team had been killed.
The earthquake shook the ground. But the news that our home on the mountain had been destroyed shook us to the core.
At Camp 1 we were unscathed, but in a bad situation. We were sure our route back through the icefall must have been destroyed. We certainly could not go up. We were stuck, with aftershocks still throwing down potentially fatal avalanches at us every 20 to 30 minutes.
The other half of our expedition was still on the icefall when the earthquake struck. We were sure they could not have survived. We were alone on the mountain, the weather too thick for helicopters to fly.
One incredibly brave climber, Damian Benegas, set out on his own the next morning through the mist to try to rebuild a route through the icefall, a painstaking and risky process of refixing ice screws and ladders over crevasses.
A lucky decision
Six hours later, an aftershock rivalling the initial earthquake set off the avalanches once again, two below us and two above. Damian's efforts were destroyed. Helicopters were now our only option.
Thankfully, on Monday the weather cleared, and I found myself tumbling into a black helicopter with a member of the British Army's Gurkhas. They had been asked to organise the evacuation of British climbers and I was on one of the first helicopters off the mountain. The rest of my expedition followed shortly afterwards, back to Base Camp.
Flying over the camp I could see great swathes of it were missing, completely flattened. Next to the landing site were the flapping orange tents covering the bodies of the victims. A shocked-looking doctor looked on in disbelief.
Eventually I found the place my tent, with all of my things, had been. My tent was gone, not just torn or spread out, but obliterated. I found one part of the case holding my equipment 500m (1,600ft) across the camp, wedged into the snow. My camera was shattered into small pieces.
On that fateful morning I had been in two minds about going up to Camp 1; I had a lot of work to do. Had I stayed, I would not have survived. One look at my tent site told me that.
Climbing Mount Everest is always dangerous, but Base Camp should not be. A series of extraordinary events had destroyed the camp, and a series of extraordinarily lucky events meant that I and my teammates at Camp 1 had survived.