What It Was Like to Hike the Alps’ Largest Glacier

Glaciers are one of nature’s most awe-inspiring phenomena—they’re also extremely vulnerable to climate change.

Distant view of six hikers along Switzerland's Great Aletsch Glacier

The Great Aletsch Glacier is the largest glacier in the Alps. It may not be around forever.

Photo by Hassen Salum/ATTA

A sea of ice surrounds me as I trek the Great Aletsch Glacier, located southeast of Bern in the heart of Switzerland—the largest, longest, thickest glacier in the Alps. In 2001, it was chosen as part of the first Alpine UNESCO World Heritage site, and it’s almost too much to take in: Spanning 31 square miles and half a mile deep in places, the glacier has a total volume of more than 10 billion tons of ice. It’s so massive it can be seen from space.

As I hear my crampons crunch solidly beneath me, I feel exhilarated. But as I look out over endless marbled ice dunes streaked with gray rock and see the deep crevasses we’ll have to navigate on this six-hour hike, I also feel a touch terrified.

“Just follow my trail exactly,” mountain guide Kurt Burgener calls to me as I hesitate on a slippery, narrow ledge. My fellow trekkers and I have been following him through a labyrinth of fissures, roped together and herded like a gaggle of preschoolers on a field trip.

If anyone is going to get us safely over this impasse, it’s Burgener. At 50, he has been a certified Swiss Alps mountain guide for half his life. He grew up next to the Aletsch and has been walking on this glacier since he was five years old.

Two people sitting on rock overlooking snowy mountains and low clouds

Switzerland’s Jungfrau-Aletsch region was named a UNESCO World Heritage site in 2001.

Photo by Hassen Salum/ATTA

I take a deep breath, place my feet in his exact boot prints, and shuffle across, keeping my gaze averted from the abyss on my right and left. Once I feel in flow with Burgener’s steps, I look up to see the sun breaking through the clouds and the rugged Bernese Alps emerging from the fog. My soul feels recharged, and I mutter one “Oh my God” after another as the glow passes over deep chasms in the ice, illuminating pops of turquoise blue. But my lightness has a counterweight to it.

Burgener points out a spot where the ice has receded, revealing jagged rock. He tells me that in the past 40 years, he has seen the ice shrink noticeably. “Year after year, or even within a few months or weeks, the approaches to the glaciers have to be adjusted or revisited,” he says. Scientists have seen it, too: Swiss glaciers had their worst melt rate in 2022, losing 6 percent of their volume. Indeed, global warming is especially visible in the Swiss Alps, where temperatures have been accelerating in the past few decades at about twice the global average. Experts warn that Alpine glaciers—and half of all glaciers in the world—might completely disappear by 2100.

When I’d read similar headlines and stats about climate change before, it had felt abstract, but here, I’m viscerally struck by what could be lost—and the opportunity that an experience like this offers. Later, when I talk to Emmanuel Salim, an assistant professor at the University of Toulouse who leads studies on how glacier tourism in the Alps is affected by climate change, he confirms what I’ve been mulling over. “Last-chance tourism is not only a matter of seeing these glaciers before they melt,” he says, “but also about understanding what is happening in our world.” By seeing climate change firsthand, he adds, we establish a personal connection to the crisis. As I blink in the face of the blinding white glacier, I know I have.

Kathleen Rellihan is a travel journalist and editor covering adventure, culture, climate, and sustainability. Formerly Newsweek‘s travel editor, she contributes to outlets such as Afar, Outside, Time, CNN Travel, and more.
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