Success and Death on Mt. Everest

How the main routes and seasons compare. If you’re going to climb Mt. Everest, you’ll first need to choose a season and a route. Until now, you’d have had to make choices without answers to questions like: Which route has the highest success rate? Which route has the highest death rate? And what about spring vs. fall? Is the mountain safer or more dangerous than it used to be?

These questions can now be answered with data were graciously supplied by Miss Elizabeth Hawley. Starting with the American Everest Expedition in 1963, she has extensively interviewed nearly every mountaineering team passing through Katmandu (see her extensive reports in the Nepal section of this AAJ, and in nearly every AAJ for the last 40 years!). Richard Salisbury has transcribed her detailed records into an extensive computer database, which will soon be published by the American Alpine Club and The Mountaineers Books. We have now mined those data. Our goal is to help mountaineers make informed decisions when planning a climb of Everest, as well as to describe some fascinating historical trends in Everest climbing.

So, what’s the surest way to reach the summit of Mt. Everest? If the past is a reliable guide to the future, then the South Col in spring offers the best chance of success. However, the North Col in spring is a close second and may even be catching up. Even so, the South Col has had the higher success in four of the past five springs. Climbers on these two routes in spring have enjoyed a remarkable 36% success rate over the past five years. That pattern does not hold on these routes in the autumn, as success rates on both routes then are strikingly reduced, especially on the North Col. Not surprisingly, climber success rates on non-main routes are relatively low, and even in spring have averaged only 12% over the past five years.

What’s the best way to survive an attempt on Everest? Climber death rates are uniformly low (1% to 2%) and essentially the same on various routes and in spring or autumn. Death rates of high-altitude porters are, however, elevated in autumn relative to spring. Surprisingly, the climber death rate on “other” routes is only slightly elevated above those for the two main routes. However, the death rate on these other routes undoubtedly underestimates the danger because only relatively skilled and experienced climbers attempt these routes.

These analyses illustrate clear historical shifts in climbing on Everest. For the first decade following the first ascent, most expeditions repeated the South Col route. Beginning in 1963 (U.S. expedition to the west ridge) and lasting through the early 90s, however, many climbers on Everest attempted alternative routes. This was an era of bold climbing, with ascents on the southwest (British, Polish, Soviet), Kangshung (American, International), and northwest faces (Japanese, Australian). One in 10 climbers even went in winter!

Times have changed. In the past five years, very few climbers attempted anything other than the two main routes. Moreover, 9 of 10 climbed in spring; and only one climber went in winter. These shifts seemingly reflect an increasing conservatism on Everest, with the vast majority of climbers concentrating on the season and routes that maximize their chance of success. Indeed, 95% of all “Seven Summiters” climbed a main route on Everest.

Even many of the elite climbers are seemingly becoming more conservative. Consider the 50 climbers who have summited 10 or more of the 8,000m peaks (including Everest). Of those who first summited Everest between 1978 and 1989, 1 in 3 climbed a non-standard route; but for those who summited thereafter, 1 in 15 climbed a non-standard route. Perhaps the expanding quest for all fourteen 8000ers is encouraging even elite climbers to just “bag” Everest and get on with the remaining peaks.

Success rates on the main routes have increased the past quarter century, yet death rates have remained stable. In some ways these patterns are surprising, given the widespread belief that contemporary Everest climbers are on average less experienced and skilled than their predecessors. If that belief is accurate, then the decline in average skill and experience has been more than balanced by improved equipment and logistics, better weather forecasting, greater cumulative knowledge of the routes, and enhanced skill and experience of high-altitude porters and leaders.

Raymond B. Huey, AAC, and Richard Salisbury, AAC