RAINY PASS -- Reached in a snowstorm near the headwaters of the Happy River high in the Alaska Range on Thursday, the improbable, 57-year-old leader in one of the world's toughest endurance races had only three words to describe the situation. They will not be repeated here to spare those troubled by course language. But readers who can sort out the acronym WTF will know exactly what he said.

Suffice to say, Pennsylvania attorney Tim Hewitt -- a man who has six times hiked the 1,000 mile Iditarod Trail to Nome -- is as surprised as anyone to be leading the Iditarod Trail Invitational on a race of 320-miles to a tiny community called McGrath on the shores of the Kuskokwim River.

Age is one of the issues here, but not the biggest. The biggest issue is mode of travel. Hewitt is a hiker and snowshoer. Every previous Invitational has been won by a cyclist on a fat-tired bike. No one on foot has ever led the race past the halfway point. No one on foot has even come close.

The race is open to all human-powered forms of transport, but cyclists have owned the trail for a decade. In previous races, the best of the people on foot or skis were usually at Rohn, a remote outpost in the heart of the range, when the Invitational winner wheeled into McGrath, another 110 miles on.

This year, though, Hewitt is at the front with noted ultra-runner Geoff Roes from Juneau not far behind. The 35-year-old Roes set a course record for the Western States 100 Endurance Run, the Super Bowl of ultra-distance running, in 2010. It is at least conceivable he would be in this position, though Roes himself scoffed at the idea.

For a couple runners on snowshoes to end up at the front of the Invitational, he said, it took "the perfect storm." Or, maybe more accurately, the perfect storms. First came big snow when the race began at Knik on Sunday. Snow fell heavily from Sunday into Monday. Racers wallowed, but those pushing bikes suffered worst.

It is not easy to push a bike through more than two feet of snow. It is especially not easy when the snow hides the old snowmachine track along which you are trying to push, and you are prone to sink waist-deep into unpacked snow. Five-time and defending Invitational champ Peter Basinger pushed hard anyway and led the race across Flathorn Lake and the Dismal Swamp to the banks of the Susitna River, about 30 miles from the start.

The hikers on snowshoes passed him and the other bikers there. Basinger has not seen them since. He thought he would catch up when the snow stopped on Tuesday. But then, as Roes duly noted, there came the wind. It drifted in the trail as surely as if there'd be another snowstorm, and when the wind stopped the temperatures got warm and the surface of the trail turned to mush.

The bikers pushed on slowly as the hikers on snowshoes kept pulling away. Some expected them to be caught by Rainy Pass Lodge on Puntilla Lake at the entrance to the pass. They weren't. By Thursday night, Hewitt was leading the race up and over the 3,160-foot high gap in the surrounding mountains.

"Unbelievable," he said.

"He's amazing," said Roes. "I have so much respect for him."

How long Hewitt can keep going is unclear. The rockhard Zastrugi that covered the trail for about 10 miles from Puntilla Lake to the Happy River was brutal -- a rough, broken surface that tilted all ways at once. It was otherworldly. Hewitt said it tripped him up and knocked him off his feet more than a dozen times.

He sprained an ankle. So now he's not just the old man at the front of the Invitational. He's the limping old man at the front of the Invitational.

"I don't know if I want to be him when I'm his age," Roes said, hinting that by then he might be into kicking back, putting his feet up, and maybe enjoying a beer or two. Not Hewitt. He's sort of proven himself the "Duracell Bunny" of the Iditarod Trail. He just keeps going and going and going.

Basinger, who remains on the trail, is confident he and sidekick Phil Hofstetter from Nome will eventually catch Hewitt and Roes. As rough at the trail was in the pass -- the frozen waves of snow pitched a snowmachine around like a boat in rough seas -- the cycling duo was riding some of the trail. It put smiles on their faces and boosted their confidence.

Roes admitted the cyclists have reason to be optimistic. There is still more than 100 miles to go in this race, and they are close enough to the lead that if they get good trail they can overtake both of the hikers at the front. But the weather has thrown so many twists into this Invitational so far, who knows.

This is Craig Medred's third year in a row covering the Iditarod Trail Invitational for Alaska Dispatch. Contact Medred at craig(at)alaskadispatch.com