NEPAL - On April 18, Good Friday, a massive avalanche of ice and snow plunged down the west shoulder of Mount Everest and slammed into a trail used by high-altitude porters. Sixteen Sherpas were killed.
In the lower section of Everest, the Khumbu Icefall has claimed many lives before. Its constantly shifting blocks of ice and snow are an ever-present danger.
But this time, the danger came from above, giving rise to the single deadliest day in the recorded history of climbing on Mount Everest.
By now, the 39 expeditions that were on the Nepal side of Everest have packed up and left, even though the impact of the tragedy will continue to reverberate for years. Ironically, on the Tibet side, teams climbing with Sherpas are continuing with their missions.
Without a doubt, the business of climbing the peak has always been a perilous affair. The chances of dying while trying to reach the top of the world are around 2 to 3 per cent by today's standards.
In more recent times, however, the burden of the risk has shifted so greatly from foreign climbers to the Sherpa high-altitude porters that the average risk borne by a Sherpa climber is at least double that faced by a foreign one.
Until the 1990s, because of the high threshold of skill needed to join an Everest expedition and other requirements such as selection into a national team, there was no shortage of people willing to be taken on as "junior" climbers, who were invited to join after having successfully undergone a selection process.
They were happy to carry loads through the Khumbu Icefall at the foot of the mountain without any guarantee of securing a place on a summit team.
Risks in those days were more evenly distributed between seasoned mountaineers and their hired, high-altitude porters, most of whom are Sherpas from the Everest region.