Fear is fine. But complacency will kill you.

The Khumbu Icefall lies between Base Camp and Camp One on the Nepal side of Mount Everest. The icefall rises 2,000 vertical feet and is one of the deadliest sections of the route, composed of massive ice towers called seracs, which can be as large as houses. The whole thing looks like an insane frozen obstacle course.

As part of an enormous glacier, the icefall is always in a state of motion and it moves at a rate of about four feet per day: When the sun comes out and the ice starts to melt, these building-sized ice chunks start to shift. Every once in a while, one or more of them will collapse onto the route, so climbers are in constant danger of being crushed. Picture yourself trying to make your way through a gigantic life-sized game of Jenga, but the blocks are made of ice rather than wood. When the wrong piece moves, the entire structure can come crashing down, demolishing everything around it. The threat is constant, and when it comes to that icefall, there is never a time or place you feel totally safe.

Yet another layer of danger comes from the fact that there are huge crevasses (deep, open cracks in the glacier) everywhere, meaning you could plunge hundreds of feet to your death. The icefall’s fearsome reputation is well-deserved and sometimes plays a role in people’s decision to climb Everest from the north side, approaching from Tibet instead of from Nepal.

As a veteran of two Everest expeditions, I’ve probably been though the icefall sixteen times. And while you would think it would become less and less frightening the more times I climbed through it, it didn’t. The sixteenth time was not any less terrifying than the first time, and here’s why: The icefall never becomes any less dangerous. Now, the more time you spend at altitude, the more acclimatized you become, and the faster you are able to climb through it. And the faster you can climb, the less time you are exposed to the hazards, so that’s good. But the risk is never gone, and plenty of experienced climbers have lost their lives while going through it. In April 2014, a serac collapsed and killed sixteen Nepali guides—most of whom had years of experience on the mountain.

The fear never went away when I was maneuvering through that area. I could feel it in my mind, in my stomach, in my chest, and in my fingers and toes. Each time I was making my way through it, I kept thinking, “How will my loved ones feel if I don’t come back from this mountain?” They’d probably say, “She died doing what she loved”—but that doesn’t change the fact that when you die on a mountain it’s usually a horrific death: a fall, cerebral edema, an avalanche, hypoxia. I was frightened all the time, and what made it worse was that I felt like such a wimp for feeling scared, because so many other climbers seemed to dance through that obstacle course of ice almost as if they were enjoying it.

In 2002, after I’d made seven uneventful passes through the icefall, Everest decided to test my nerves by unleashing an avalanche during my eighth time passing through. I heard a thundering sound and looked up—only to see 10,000 tons of ice barreling down toward my team. I closed my eyes and held my breath...and the entire slide stopped just a few feet from us.

I had no idea I would be back eight years later, rolling the ice dice again.

In 2010, my attitude was different. Okay, I was still totally scared! What had changed, though, was the way I thought about my fear. I stopped beating myself up for feeling scared and started embracing it. I knew there was still a tremendous amount of risk present, but I focused on my surroundings. I was more agile, more able to adapt and move quickly when the ice around me moved and shifted. And this experience taught me one of the most critical lessons about mountaineering, business, leadership, and life: Fear is fine—it’s just a normal, human emotion. But complacency will kill you.

Fear is what kept me awake and alert. It motivated me to continue to constantly survey my surroundings as I was making my way up a very big mountain. at fear is what kept me alive.

Levine M.B.A. ’00 is an adventurer who served as team captain of the first American Women’s Everest Expedition, climbed the highest peak on all seven continents, and skied to both the North and South Poles. She spent four years on the part-time faculty at West Point, where she lectured on the topic of leading teams in extreme environments.