One night, in Camp 2, they heard a boom emanating from Camp 3. An avalanche had descended on part of Camp 3, shredding the tents they had placed in advance. If Kedrowski and LeDuc had been in Camp 3, as planned, both would've been killed.
More trouble ensued when LeDuc's Sherpa was injured in a rock fall. He had to be airlifted off the mountain.
The next day, they saw people near the south summit. Kedrowski assumed they were summiting, that the weather window was holding. A day of climbing passed before he realized the climbers were beginning their descent.
At Camp 4, Kedrowski and LeDuc's team realized something was wrong. People were being carried into camp unconscious, their faces iced over. It was hard to tell who was alive.
"Is that normal?" they asked one another.
A storm moved in. The winds lashed the camp. Five or six lightning strikes flashed in the sky as visibility neared nil. Kedrowski and LeDuc couldn't see 3 feet in front of them. They began encountering dead and dying climbers, one of them Klorfine.
At one point, a 100-mph gust blew Kedrowski off his feet.
"My face felt like it was being sandblasted," he said.
They had no choice but to turn around, but LeDuc's regulator froze, cutting off her oxygen. Sherpas had to revive her.
Kedrowski soon encountered Song Wondin, the climber Ben Yehuda would find dead. His mitten was off. Kedroswki tried to hand it back to him. Wondin looked at him with frozen eyes -- icicles hanging from his beard -- swatted the mitten away and passed out.
Kedrowski tried to pick him up, but he was unwieldy, almost dead. He waited for other members of his team to descend, but it was too late.
Almost everyone on the team sustained an injury. One had a broken rib, another a frozen cornea. They were exhausted, traumatized. They sat in tents at Camp 2, reeling, shell-shocked, before returning to base camp.
Kedrowski and LeDuc were beat, but not beaten. They recovered in time for the season's last weather window, May 26, which was forecast to bring calm winds.
Climbing harder and faster than they'd ever climbed, they skipped camps 1 and 3, making the four-day trek in two. They stood atop Everest on the last possible day.
Kedrowski shed a few tears, and Sandra, who often found it difficult to relish her accomplishments, found a moment she could relive forever.
The summit itself is quick -- snap photos, pose with your flag, take in the panorama and descend -- but the memory endures forever. Still, their journey was only half over.
They had to find the energy to get back down after being awake for 38 hours. It wasn't until they reached base camp that relief set in. Kedrowski hugged LeDuc and said, "Now I know we're going to live."
"It was this amazing, surreal feeling, this energy coming from elsewhere," LeDuc said. "I like to think there were a lot of people home who were thinking of me and that support carried me."
A year later
A year has passed since their expeditions. Kedrowski and LeDuc still love climbing, but the experience has changed them.
LeDuc's 60 Twitter followers ballooned to thousands who wanted to follow her journey. Media reached out, asking her to elaborate on something she tweeted via her brother: "Lots of dead or dying bodies. Thought I was in a morgue."
People falsely assumed she ignored climbers in need.
"The first thing I saw was a team bringing down this woman with her face frozen solid, eyes shut and she was groaning this awful sound. Then we came across the people who had perished," she said. "That was what my tweet was about,"
Asked if she blamed overcrowding for the 2012 deaths, LeDuc was torn.
"I can't fault the crowds for being there because I wanted to be there," she said. "You can't prevent people from having these kinds of dreams. It's addictive and beautiful at the same time."