You can hear it in their voices, a sense of anticipation that comes with preparing to do something so invigorating.
Meet the winter men of the mountains, four guys who love to run, explore and savor the sweet taste of adventure.
Tim Twietmeyer, Bill Finkbeiner and Jim Northey, all from Auburn, and San Francisco's Dean Karnazes plan a winter crossing of the Sierra Nevada on foot from Squaw Valley to Auburn, roughly following the 100-mile course used for the Western States Endurance Run.
They hope to start Jan. 2 at 4 a.m., subjecting themselves to snow, freezing temperatures and potential avalanches, among other hazards, as they make their way through the Sierra.
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If the words "Donner Party" come to mind, you might not be too far off course, although these four athletes -- all husbands and fathers -- don't quite see it that way.
"It's just the spirit of exploration, to see if it can be done," said Karnazes, a 38-year-old small-business owner. "It's both a physical and a mental challenge, to push your body beyond the limits. We'll see how it goes."
Consider this foursome well-prepared. Check out their credentials:
* Twietmeyer, who conceived the idea, knows every inch of the Western States Trail. He has finished the race on 22 occasions, winning five times. The 45-year-old engineering project manager and father of three also has completed more than 120 ultramarathons, 65 marathons and an assortment of adventure races.
"It's been on the things-to-do-before-you-get-too-old list," Twietmeyer said with a chuckle. "I'm getting pretty stoked."
Karnazes, the father of two, finished fourth in the Western States last June, just ahead of Twietmeyer, and has run approximately 100 ultras, including a half-dozen 200-milers. Then there was the time two years ago when a plane dropped him off 26.2 miles from the South Pole so he could run a marathon at 9,300-foot elevation in sub-zero temperatures.
"That was a near-death experience," said Karnazes, a 2:40 marathoner who needed more than 9 hours to finish that run.
And this winter Western States idea?
"It seemed brilliant from the second he (Twietmeyer) told me," Karnazes said. "Unthinkable and crazy, something I definitely wanted to do."
Finkbeiner counts 150 ultras, 39 of them 100-milers, on his résumé. Another Western States regular, the 48-year-old landscape contractor and father of two says he has run every day for the last 24 years.
"As soon as I heard these guys were doing it, I wanted to join them," he said.
Northey, a 47-year-old custom home builder and father of three, runs partly to minimize seizures that stem from head trauma he suffered four years ago. Endurance mountain biking is Northey's forte, but he also has completed an estimated 30 ultras and 15 adventure races and is a skilled navigator.
"I'm there to make sure everybody's safe, make sure they're not in over their heads," he said. "I've crossed a portion of the Sierra in every manner you can think of, except in snowshoes.
"The main reason I do it (run) is so I can basically live. People like Tim and Dean and Bill are great motivators for me."
The winter crossing has become a hot topic in the local running community.
"It reminds me a little bit of the Donner Party," said Greg Soderlund, the Western States Endurance Run's race director. "I read the book 'Trial by Hunger' in '92 and at the time thought, What a neat thing to do, to do the winter crossing of the Western States.
"They're going to go a long ways without aid. Only the fittest of the fit can do this, should even consider this."
Said John Mansoor, race director of the California International Marathon: "All I can say is, Bring a lot of food."
Twietmeyer, well-known for returning to the finish line at the Western States to encourage slower runners, said the idea came to him three years ago after reading about a man who wrote a letter in 1858 detailing a similar winter crossing.
According to the letter, Maurice Bucke survived but later had both feet amputated. His traveling companion, Allan Grosh, died after reaching Last Chance, about 43 miles into the Western States Trail. Their mule was killed for food along the way.
This modern-day group anticipates a better outcome.
"I kind of got this idea, you know, it would be kind of cool to follow the trail in the wintertime, see what it would be like," said Twietmeyer, who has been training in snowshoes on weekend treks to the mountains. "I had to find somebody that would want to do it with me. I didn't want to go out there by myself."
So Twietmeyer asked Karnazes. The duo planned the crossing in each of the last two years, but bad weather prevented them from starting the journey.
This time, they've moved up the scheduled date from February to January, hoping for better weather. But if a big storm blows in, the plan is to wait for better conditions.
"You lose a lot of daylight," Twietmeyer said of an early winter crossing. "But your chances of running into giant snowdrifts and avalanches is reduced. It's a matter of mitigating the risks. We're not out there to try and re-enact the Donner Party or anything."
This foursome will have plenty of advantages the Donner Party and Maurice Bucke didn't.
Twietmeyer has mapped out the high country on GPS equipment, technology that will help the adventurers follow a trail at times buried in snow.
Critical equipment includes an avalanche shovel and probe, an AvaLung -- a device that allows a person to breathe if caught in an avalanche -- and other helpful tools such as snowshoes, a satellite phone, a first-aid kit, winter socks and Gore-Tex pants.
Everyone will be carrying more stuff than he's accustomed to during ultra races.
"It's uncharted territory back there," Karnazes said. "Even with the best planning, you never know what you'll need."
A four-person support crew on snowmobiles is scheduled to bring in other supplies and keep an eye on the group.
"The technology is there now to be able to do it safely," said Soderlund, who plans to serve as part of the support team. "They're doing it early enough in the season; right now the snowpack is around 5 feet. There shouldn't be much risk."
The trail from Squaw Valley ascends for 4 1/2 miles to Emigrant Pass, 8,750 feet above sea level, before heading along rugged Red Star Ridge and then dropping down to Robinson Flat at the 30-mile mark.
Trouble lurks in the high country, where snow and avalanche potential might make for slow, dangerous going.
"I've done a lot of shoeing and skiing; you really need to take your time there," Northey said. "There's a lot of danger there.
"We'll see what Mother Nature gives us."
Finkbeiner, who crosses the Sierra on the Western States trail every May, wonders how much harder a January crossing will be.
"The fresh snow could be a lot tougher if you're pulling snowshoes out of 16-inch holes you make every step," he said. "That's going to be a lot of work. I hope it's not like that."
If someone runs into trouble in the high country, Twietmeyer is counting on snowmobile support. Soderlund and crew plan to ride in from Robinson Flat to the 17-mile mark on Red Star Ridge to provide aid.
From Robinson Flat, the trail drops into a series of canyons before reaching Michigan Bluff and Foresthill, the 62-mile mark. The trail then descends to the American River at 78 miles, although this party isn't sure if it will attempt a river crossing.
"Some of the (river) crossings in the winter, they're treacherous," said Mansoor, a veteran snowcamper.
If the four adventurers cross the American River, they'll climb out of the river canyon and head up toward Auburn Lake Trails before crossing Highway 49 and climbing into Auburn.
If they don't, they'll stay on the Foresthill side of the river and head into Auburn along Auburn-Foresthill Road.
The idea is to reach the courthouse in Auburn -- the Western States race finishes at Placer High School, but Twietmeyer wants to follow the likely route of gold miners -- together and in decent shape, no matter how long it takes.
Karnazes and Twietmeyer finished the 2003 Western States in less than 18 hours; Finkbeiner broke the 23-hour mark. Northey last finished the Western States in 1994 in just under 27 hours.
"I think everybody sticks together, and if anybody wants to bail, just bail," Twietmeyer said.
Bail? On something this fun?
"I would hate to not finish it," Finkbeiner said.
Said Karnazes: "I see about 30 to 40 hours of torture."
Northey envisions simply savoring the journey.
"We race all season long," he said.
"It would be a nice experience to actually take our time and enjoy it."
Will this be the start of something new, like when Gordy Ainsleigh opted to cover the Western States Trail in the 1974 Tevis Cup without a horse, thus starting the Western States Endurance Run?
"I think it's going to be a one-time thing," said Soderlund, who offered another intriguing scenario for the future. "I'm surprised no one has done the race in reverse. No one's ever done it."
Hmmm ... any takers?