One of Mt. Everest's deadliest passages is growing even more treacherous

Navigating the Khumbu Icefall involves crossing ladders laid over crevasses that can be up to hundreds of feet deep. Jason Maehl/Getty Images

• The 2024 Mount Everest climbing season was delayed due to crumbling ice in the Khumbu Icefall. 
• The Khumbu Icefall is one of the most dangerous obstacles to cross on the path to Everest’s summit.
• As global temperatures rise due to climate change, this icefall will only become more treacherous.

Climbing Mt. Everest is a dangerous endeavor right from the start. Before climbers summiting via the South Col route can even make it to Camp 1, they must face one of the deadliest passages of all. A 1.6-mile stretch of slowly cascading ice just above Base Camp called the Khumbu Icefall.

It’s a treacherous maze of crevasses that can stretch over 300-feet-deep and house-sized “ice towers” that can break free unexpectedly, triggering deadly avalanches like the one that killed three Sherpas last year.

The Khumbu Icefall looks like a frozen waterfall. Ice slowly falls down the mountain as the Khumbu glacier recedes. InnerPeaceSeeker/Getty Images

It’s called an icefall because it looks like a frozen waterfall, but here on Everest, the term “fall” might as well be a dire warning to all. As of 2016, six people had fallen to their deaths, and that’s just a small portion of the total lives lost to the Khumbu.

This icefall is so perilous a dedicated team of specialized workers is responsible for charting a safe route through it. They’re called the Icefall Doctors, and this year, they delayed Everest’s climbing season by 12 days due to unsafe conditions on the Khumbu Icefall.

And it will only become more dangerous as global temperatures rise, Paul Mayewski, Mount Everest researcher and climatologist at the University of Maine, told Business Insider. He studies how climate change is affecting the highest peaks on our planet.

What makes the Khumbu Icefall so dangerous

Deep crevasses and deadly avalanches make the Khumbu Icefalls one of the most challenging, and dangerous passages to summiting Everest. Olaf Rieck/Wikimedia Commons

The Khumbu Icefall is essentially a slow-moving river of ice that gradually falls down the mountain as the Khumbu Glacier recedes.

Its movement is what makes it so unstable, giving rise to deep crevasses and deadly avalanches.

Between 1953 and 2019, 45 people lost their lives on the Khumbu Icefall. The three major causes of death were avalanches onto the icefall (49% of deaths), icefall collapse (33%), and falling into a crevasse (13%), according to Alan Arnette, a Mount Everest summiter and climbing coach who writes a blog about the mountain.

At the beginning of each climbing season, the Icefall Doctors are the first to traverse this treacherous icefall. They find the safest route through it, laying ropes and ladders along the way to help people navigate its cliffs and crevasses.

This year, the Icefall Doctors repeatedly encountered dangers that slowed their process. Insufficient winter snowfall and high temperatures destabilized ice towers and bridges, forcing them to re-evaluate their route several times, Outside reported.

“Going up there one part of the day and coming down the next day could look very different. And the probability of that getting worse with a warmer climate increases,” Mayewski said.

Climate change is messing with the Khumbu Icefall

As global temperatures rise, melting ice is making the Khumbu Icefall even more unstable. Jason Maehl/Getty Images

Rapid melting causes glaciers, like the Khumbu Glacier, to shrink and erode. In turn, this leads to more lakes and streams, but on a more dangerous level it also increases the risk of avalanches, ice falls, and crevasses, Mayewski said.

“The likelihood of that getting worse in a warmer climate increases because ice becomes more mobile,” he said. “The warmer it is, the more flowing water. And that flowing water obviously destabilizes the ice.”

Mayewski’s research suggests that conditions are changing all over Mount Everest, not just in this region. His study of the South Col, Everest’s highest glacier, revealed that one-third of its ice has disappeared in the last two to three decades.

“Even just walking around base camp, it’s very obvious that there’s been a lot of melting,” he said.

These aren’t the only dangers

You have a far greater chance of dying from mountain sickness on Everest than falling into a crevasse. Jason Maehl/Getty Images

While it’s clear that climate change is making conditions in the Khumbu Icefall more dangerous, not all risks on Mount Everest are related to climate, Arnette points out.

In 2023, the deadliest climbing year in Mt. Everset’s history, 15 of the 18 total deaths were caused by acute mountain sickness, falls, and disappearances. He feels that most of these deaths were likely preventable.

For example, acute mountain sickness — a mild form of altitude sickness — can be treated if climbers and their guides recognize the symptoms quickly and get to lower elevation, Arnette said. But if climbers choose to keep going, their condition can turn deadly. AMS claimed eight lives on Everest last year, according to the Himalayan Database.

Arnette believes that introducing more safety enforcement on the mountain would go a long way to reduce fatalities.

Climbers sometimes put themselves at risk too, by opting for low-cost operators, tackling Everest without enough climbing experience, or refusing to turn back even when showing signs of illness. In that last case, Sherpas often have difficulty convincing their clients to throw in the towel due to language and cultural barriers, Arnette said.

Will the added risks driven by climate change make climbing Everest impossible one day? Mayewski doesn’t think so.

“Will people still be able to do it? Yeah, I think they will. Will it be more dangerous? Arguably yes — it’s already pretty dangerous,” he said.

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