"I shouldn't have run up so fast on the first two laps," Nelson said before barreling off the summit down a narrow catwalk cut in the deep snow. And he had at least nine more hours of running ahead in the endurance challenge called Running Up For Air.
This is a race to the top, and to the bottom, and to the top again, for 12 or 24 hours.
"It's really hard conditions. We have that first-lap optimism, but you can still see that look of fear in most people's eyes," said race director and founder Jared Campbell a few hours into the race that started at 6 a.m.
Jill Bohney, a second-time participant, was determined to run hard and have fun.
"It's a good cause, first and foremost; second, awesome workout and all my friends are up here. It's a social event," Bohney said on the summit where cowbells clanged and runners cheered one other on.
"Being in a community of suffering is awesome," said Salt Lake City physician Brad Harris as he headed up Church Fork for his second tour up the mountain through the snow-covered branches of gambol oak that lined the trail.
The event started recently as a fundraiser to support Breathe Utah, a group advocating for clean air, and is now sponsored by Patagonia, Black Diamond and other outdoor-gear producers.
Campbell had been doing midwinter training runs up and down Grandeur's steeper western face to prepare for the Barkley Marathons, a springtime ordeal in Tennessee better known as "the race that eats its young" and worthy of its plural title. Few participants finish the 130-mile event; Campbell has completed it three times, winning in 2014 and 2016.
"All this time spent do something for myself; how can I do something constructive with this?" said Campbell, who has turned his family's Highland Park home into a laboratory for renewable energy. "It aligned with a need to do a crazy training day. Why not raise a few bucks doing this?"
Mid-February has other advantages for a footrace. This foothill terrain is usually covered in snow, which protects the trail surface. And the Wasatch Front is just emerging from inversion season; close enough for air pollution to be on people's minds, but far enough away to not contaminate racers' lungs.
Campbell's Grandeur climb became an annual group run, and last year it was staged as an officially sanctioned event, complete with a permit from the Uinta-Wasatch-Cache National Forest. Now it is staged in Church Fork, where a 2.9-mile trail heads up the southeastern side of the mountain, climbing 2,560 vertical feet.
In comparison with Barkley, the Grandeur run is a picnic but still a challenge that can test the limits of most runners.
The 13 laps Campbell completed last year translate into 76 miles and 33,000 vertical feet. That's the equivalent of running up and down Mount Everest from sea level, just without the glaciers, thin air, howling winds and subzero temperatures.
"We are all out here by choice; you have no right to complain," said volunteer Curtis Thomas. "It's beautiful. It worked out well for the racers.
"Coming up the night before was a different story," laughed Thomas, who scaled the mountain Friday to set up the aid station and tent in the wind and rain. He and other crew members weathered the night with a bottle of cinnamon-flavored whiskey. The rain eventually turned to snow, and about 7 fresh inches covered the summit by morning.
"That was a relief. Spirits are high," Thomas said as he headed down the trail Saturday morning, the race not slated to finish until 6 a.m. Sunday.