It was the final climb on his quest to reach the highest summit on all seven continents. When Christopher Kulish finally reached Mount Everest's 29,035-foot peak, he joined an elite group known as the "Seven Summits Club."
But the 62-year-old Colorado attorney died Monday after returning to the first camp below the mountain's summit. He's the second American to die in the past week after reaching Everest's highest point.
His family believes the cause was cardiac arrest, according to the Denver Post.
"He saw his last sunrise from the highest peak on Earth," his brother, Mark Kulish, said in a statement to The Denver Post. "We are heartbroken at this news."
Last week, 55-year-old Donald Lynn Cash of Utah collapsed and died just after reaching the Everest peak. He, too, had reached the highest point on all seven continents.
At least 11 people have died on Mount Everest this year.
The deaths come amid reports of overcrowding on the popular mountain. The Nepali government granted 381 permits to climb Everest this year, a number that doesn't include guides who are on the mountain as well. For some climbers, that traffic has meant longer wait times - some told the Himalayan Times the wait has exceeded two hours between the last camp and the peak.
There's also been debate over whether the bottleneck is a result of more inexperienced climbers crowding the mountain. Mountaineering experts suggest that experience level and various factors causing crowding are contributing to this season's death rate.
Mountaineer Vanessa O'Brien, who has also climbed the seven summits, said when there's a crowd, being a more experienced climber won't help.
"It doesn't matter if you're the best race car driver in the world. If you're stuck in traffic, you're struck in traffic," she said in an interview.
And when a climber is stuck in Everest traffic, "their body is starting to deteriorate." O'Brien, who set a record as the fastest woman to reach the highest peak on every continent, also said the descent is often harder than the climb.
"You have given up so much energy to get up there and now you're only halfway," she said.
Climbing expert Alan Arnette said there's no simple explanation for the string of deaths. He said weather that has led to a shorter climbing season is one factor causing overcrowding. He also said the cost to climb Mount Everest has decreased, which means more people are making the journey. He urged the governments in charge of granting permits to limit how many people can be on the mountain at once.