KOYUKUK — The lead pack of Iditarod teams arrived here Saturday, six days and 580 miles into the race across Alaska.

Two Rivers musher Aliy Zirkle blew through on her way down trail to the Nulato checkpoint, back on the normal Iditarod Trail Sled Dog Race with a full team of 16 dogs coming off a 24-hour layover the day before.

The race was rerouted through the Interior because of a lack of snow.

Denali musher Jeff King, a four-time Iditarod Trail Sled Dog Race champ, had arrived in Koyukuk about 9 a.m. but rested for several hours. He also came in with a full team of 16 and dropped one dog here. Zirkle stayed only four minutes before stopping down trail about 20 miles in Nulato and taking her only other mandatory rest stop of eight hours there.

Late Saturday, it was Nome’s Aaron Burmeister leading the pack, with King, last year’s champ Dallas Seavey and Zirkle giving chase. Zirkle has been the race’s runner-up the last three years in a row.

The volunteer checker in Koyukuk, Nina Schwinghammer, said Zirkle seemed like she was in a hurry grabbing snacks from one of her drop bags here.

“You could tell her mind was on the next few miles ahead,” Schwinghammer said. “She came by, ripped open a bag, stuffed it in her sled, and took off.”

While King was in the National Guard armory here, two-time champ Mitch Seavey, of Sterling, mushed his 13-dog team quietly into this village of 100 people on the Koyukuk River. Seavey parked the dogs and got to work ripping apart straw to bed down the dogs. He discussed dropping a dog with the veterinarians checking the team.

His son, Dallas, came in about 2:20 p.m. and left four hours later.

Farther behind, two Iditarod mushers scratched Saturday. Anchorage’s Christine Roalofs called it quits in Ruby, and Talkeetna’s Gerald Sousa ended his race in Galena. Both said it was in the best interests of their dogs.

Burmeister had followed Zirkle out of Koyukuk by about two hours and only stayed here for 10 minutes. He stopped in Nulato for five minutes and mushed more than two hours to Kaltag, where he arrived first a little before 9 p.m. As of 10 p.m., Burmeister was still in Kaltag.

During his brief stop in Koyukuk earlier, Burmeister grabbed plastic for his sled runners from a drop bag and gave snacks of fish and beef to his team of 13 dogs, who all scarfed down the treats. He also left behind a small tag sled on the back of his main sled.

“You hungry?” he said in a singsong voice to the dogs while feeding them. “Watch my fingers.”

King still was preparing to leave about 3 p.m.

While walking from the armory to where his dogs were parked next to Mitch Seavey’s, King said he and the others were starting to get a glimpse of how the race might turn out in the final stretch. The temperature had dropped to colder than 40 below during both the Iditarod and Yukon Quest, from which King scratched after a frigid cold spell.

Mushing toward Koyukuk, King had fallen asleep and was knocked off his sled by a branch. The team kept going, and King said he thought that might have been the end of the race for him.

“They did not stop with just a, ‘Whoa.’ And off they went,” King said.

But the dogs did stop, eventually, after about a mile, and it only took King 20 minutes to catch up to them, he said.

“I went up and gave ’em a big hug, and thank God we’re right back in it,” King said.

King was leading the 2014 Iditarod in the last few miles of the race when gusting wind on the coastline trail to Nome forced him to scratch out of concern for his dogs and himself. Asked if finishing this year’s race, his 25th, meant more to him after the Quest scratch and the shutdown in Iditarod last year, King said he was due for a good finish.

“I’m ready for one ending well,” he said. “But I voluntarily pulled out of the Quest to save the team for this race. And last year’s Iditarod was just bizarre.”

“They all mean a lot, but I’m due for a good one,” he said.

Parallel to King’s team was the older Seavey, who looked up and greeted his competitor of many years.

“Howdy,” both men said to each other.

“Wasn’t that fun?” said Seavey, who had stopped to camp twice on the cold run to Koyukuk.

“You’re a glutton for punishment,” King said, both of them chuckling briefly before getting back to work.

Staff writer Casey Grove is the News-Miner’s Anchorage reporter and is covering the Iditarod this year. Follow him on Twitter: @kcgrove.