Web ExclusiveIn April, a high-altitude avalanche killed 12 Sherpa guides and seriously wounded three in the single deadliest accident on Mount Everest, according to news reports.

A group of about 50 people, mostly Nepali Sherpas, were hit by the avalanche at more than 20,000 feet.

Between May 15 and 30 is usually the best window for reaching the 29,028-foot peak, according to experts. Climbers arrive in April to acclimate to the altitude before heading toward the summit of the world's highest mountain.

About 334 foreign climbers had been given permission to climb Everest during the next few months, with an estimated 400 Sherpas helping them, according to mountaineering officials.

Until the late 1970s, only a handful of climbers reached the top each year. The number topped 100 for the first time in 1993. By 2004, it was more than 300. In 2012, the number was more than 500.

Scaling Everest has become something of a booming niche business for elite, wealthy adventurers, many of them it must be said are experienced climbers from around the world, and the tour companies that guide them.

One Sherpa climber said one or two companies this spring were taking risks for business purposes.

Wow. Like we’ve never see that in the workplace world…

With increasing numbers of people climbing the mountain in recent years, Everest has frequently become a bottleneck, with climbers forced to wait significant amounts of time for their turn on the ropes, leading to problems in getting climbers efficiently up and down the mountain, according to experts.

The disaster in May 10-11, 1996, chronicled in Jon Krakauer's Into Thin Air (1997) was partially caused by the sheer number of climbers (34 on that day) attempting to ascend, causing bottlenecks at the Hillary Step and delaying many climbers, most of whom summitted after the usual 2 pm turnaround time. Krakauer proposed banning bottled oxygen except for emergency cases, arguing that this would both decrease the growing pollution on Everest—many bottles have accumulated on its slopes—and keep marginally qualified climbers off the mountain.

By the end of the 2010 climbing season, there had been 5,104 ascents to the summit by about 3,142 individuals, with 77% of these ascents being accomplished since 2000, according to Wikipedia . On May 23rd 2010, the summit of Mount Everest was reached by 169 climbers – more summits in a single day than in the cumulative 31 years from the first successful summit in 1953 through 1983, according to Wikipedia.

Climbing Mount Everest can be an expensive undertaking for climbers, with total costs upwards of $50,000-$100,000+ -- $8,000 for training; $10,000 for gear;  $35,000 to $100,000 for mountain permits and climbing guides and bottled oxygen; $1,500 to $3,500 to fly to Nepal; and upwards of $1,500 in cell phone bills, according to the article “The Economics of Everest,” by Katherine Tarbox.

Tarbox quoted one climber after his first attempt to scale the mountain K2: “I had done it myself and found not only that the pearl of great price was worth far more than I possessed, but also that the very peril and privations of the quest were themselves my dearest memories.”

And we wonder why some people will risk it all…