Heather Siirtola carries an invisible red lantern and a whole lot of sisu.

You can't see either of those things, but if she employs them successfully they could guide her to the finish line of the Last Great Race on Earth.

And that's all she wants: To finish the Iditarod Trail Sled Dog Race. First, though, a shower and a nap would be nice.

After a week of toughing out below-zero weather and ridiculously rugged trail conditions, Siirtola found some creature comforts in Alaska on Saturday. The Bismarck native, competing in her first Iditarod, checked into the town of McGrath late Friday. She called home to Bismarck on Saturday afternoon, sounding extraordinarily tired, but still full of the drive one needs to complete an 1,100-mile race through the Alaskan wilderness.

Siirtola's Finnish ancestors called that grit "sisu." It's something she's always had, her friends and family said. Although she's in last place, Siirtola sounded determined to continue when she talked to her family from McGrath.

"She said she's really tired, and many times she said she thought about quitting," her father, Jim Siirtola, said. "But she told herself she has to keep going. That's Heather."

Siirtola took a mandatory 24-hour break in McGrath on Saturday, a town that would fit between Carson and New England, population-wise. On the Iditarod Trail, that's a metropolis. McGrath has a 24-hour kitchen, coin-operated showers and a bar and restaurant. Siirtola would have to stay there until at least 9:30 p.m. She called home for just a few minutes in the afternoon before going back to sleep.

While she was resting, her traveling partner for the past few legs of the race, Grand Forks native Ellen Halverson, left for the next checkpoint. That dropped Siirtola to last place among the 62 mushers left in the competition. In Iditarod tradition, the final musher in the race is said to be carrying the red lantern.

If she can carry it to the finish line in Nome - still 722 miles ahead of her on the trail - that would be fine with Siirtola. Before the race, she aspired not to win, but to finish with healthy dogs.

It could be those dogs, and not the sled driver, who determine whether Siirtola will complete the race. She had already lost six by the time she reached McGrath, which left her with 10 animals to pull her sled. She probably cares more about her dogs' health than her own, Siirtola's grandfather, Dale Ennen, said.

"When she makes up her mind to do something, she does it. The only thing that would stop her is if she loses more dogs," Ennen, of Bismarck, said. "She's got a lot of guts. I wouldn't have done this when Iwas young. She's very strong-willed."

Siirtola, 29, was one of 12 women to start in this year's 82-team race. By Saturday afternoon, 19 mushers - or about 23 percent of the field - had scratched. According to the Iditarod Web site, more people have climbed Mount Everest than finished the famous sled-dog race. Just 617 teams have completed the Iditarod, which is in its 35th year.

Siirtola has gone 400 miles, and should have a couple of relatively easy legs in her immediate future. The stretch from McGrath to the next hub of Takotna is 18 miles of well-traveled trail. After Takotna is a 25-mile leg to the ghost town of Ophir. The current race leaders reached Ophir last Wednesday.

The pack of leaders, as of Saturday, was in Eagle River - 300 miles ahead of Siirtola's position.

Siirtola has already survived blizzard conditions and getting soaked on an open stretch of river. At one point, she had to return to the checkpoint in Rohn so she could dry out and warm up her wet feet.

"She said she was just laughing out loud during the white-outs," Jim Siirtola said. "She said sometimes laughing is the only way to keep your sanity up there."

The toughest parts of the trail, weather-wise, could lie ahead. The long stretch along the Yukon River, where the leaders were gathered Saturday, is often cold, very windy and barren. The cold temperatures and high winds don't improve as the mushers near the Bering Sea and the finish line in Nome.

That worries Siirtola's mother, Deb Stuart.

Still, Stuart - a breast-cancer survivor - could be Siirtola's biggest supporter.

"From a mother's standpoint, Ikind of cringe when I think about her being up there all alone," Stuart said. "But I'm so happy she's doing it. Every day is a blessing, and she's taking advantage of that."

Siirtola's stepfather, Dann Stuart, left for Nome on Saturday. He hopes to meet Heather at the finish line. Her mother, meanwhile, updates Siirtola's hardcorehuskies.com Web site whenever there's news.

(Reach reporter Tony Spilde at 250-8260 or tony.spilde@;bismarcktribune.com.)