Only now, at the end of my journey, do I feel confident, after seven weeks and a hundred miles traveled on skis. I have been on a scientific expedition that has gone out every year since 1946 to study the Juneau Ice Field glaciers on the Alaskan-Canadian border. We are fifty students and professors reading the glaciers as highly sensitive instruments for measuring climate change.

We started in the Juneau rain forest and made our way toward Atlin, British Columbia. After reaching the névé line, where the snow stops and the blue ice starts, we took off our skis and attached them to the sides of our packs. I suddenly had a sense of what it would be like to be eight feet tall. Then it was only three miles of jumping crevasses or hiking alongside them when the gap across the eerie blue nothingness is too wide.

By day, we tracked the glacier’s movement: We set out stakes in a straight line running from one side of the glacier to the other, recording our geographic location at each stake. Because glaciers move faster at their center than at their sides, after two weeks the line is bent into a V. By recording the new position of each stake, we can calculate the glacier’s velocity.

By night, professors gave lectures. One of them told us, “If it weren’t for the science, we would just be another lame Outward Bound program.” The science gives our adventure a purpose, as it did for Darwin and all the other great field scientists of the nineteenth and early twentieth centuries. It’s hard to know which draws me more: the science or the adventure.

I spent my last week scraping circles around a mountain on crampons, looking for markers from last summer’s boundary between ice and rock. The line of stakes had moved significantly lower down, part of a trend we think relates to global warming. While collecting the data, we experienced whiteouts, and the numbers on my notepad got larger and larger as my fingers became colder and colder.

The expedition group has come to feel like my tribe in this vast and barren wilderness where the only permanent residents are algae and lichen. Sometimes during this trip I felt shipwrecked, floating on a pair of skis in an ocean of snow. At other times I looked down at my feet as I hiked along and imagined I was walking on the surface of a tooth riddled with cavities. Now, at the end of my journey, rain falls and I’ve been wet all day, but I cannot stop turning to look back at the sublime white snow and the outline of peaks. At times I have used them to navigate, like a sailor reading the stars.

Only when I see trees again do I realize the absence of odors on the ice field. Sound, however, is greatly amplified there, and the valleys reverberate with echoes. Many days all I wanted was silence, but the wind came in through my ears. I learned that the only way to keep moving was to sing and scream, “WAHOOOOOOO!” at the top of my lungs.

In my last steps off the ice, the weight of ordinary time and space return. We carry the data from the ice field, but we’ve collected something more as well. I’ve discovered that science is as much about the thrill of gathering numbers as it is about studying them. For me the dry data will always suggest the Northern Lights over an expanse of mountains, their dances like the lights in a 1970s-style roller-skating rink. I will always remember the cringe of my feet before I get out of bed, as they anticipate the wet, rotten wood floor of my cabin.

I know that after this, school will be tedious with neat and tidy textbooks and lectures. I know from my own chattering teeth, and from wearing the same muddy clothes all summer, that science is more than that. It’s people, dirt, rock—and a lot of decisions made on the fly.

Geology and biology concentrator Anna Henderson is now an intern at the Joint Oceanographic Institution in Washington, D.C.