A 55-year-old Utah man who told his son that he was "so blessed" to achieve his lifelong dream of reaching the summit of Mount Everest, collapsed and died during his descent on Wednesday.

The family of Donald Lynn Cash, of Sandy, Utah, said the software sales executive and mountaineer apparently died of a heart attack. His body is not recoverable.

"The last message he sent to me personally was, 'I'm so blessed to be on the mountain I have read about for 40 years!' " son Tanner Cash told NBC's Today show.

Cash fell at the top of the summit in the early morning, according to The Himalayan Times, and was brought below the famed Hillary Step on the south side of the mountain by his climbing guides. They tried to save his life by administering oxygen, but he died later in the afternoon.

There are reports that the effort to carry Cash below the Hillary Step was delayed by a traffic jam of other mountaineers trying to reach the summit. Somewhere between 250 to 300 climbers were attempting to reach the summit on Wednesday, according to The New York Times.

"There's a long queue of climbers above Camp IV," Gyanendra Shrestha, a liaison officer at the Everest base camp, told The Himalayan Times. "Everyone seems in a hurry to reach the summit point when the weather is clear."

Cash died as he achieved his goal of climbing highest summits on all seven continents.

"I am truly blessed to be able to take the next 5 months off on a sabbatical to finish the last 2 remaining mountains on my Seven Summits Club dream," he wrote on his LinkedIn page. "Mt. Vinson-Masiff in Antarctica Jan 7-26th, 2019 and then Mt. Everest in Nepal April/May 2019. I'm excited to look for the next chapter of my career in June when I return. Safely. With all my digits."

I think there's just so much peace that comes from knowing that he didn't suffer," Cash's daughter Brandalin told NBC's Today show. "That it was the best way to go."

Cash is the 12th mountaineer to die on Himalayan mountains above 25,000 feet in the spring climbing season, The Himalayan Times reports.

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