On Tuesday, Iditarod musher Aliy Zirkle came in to the White Mountain checkpoint at 5:24 a.m. -- just 13 minutes behind 2004 champion Mitch Seavey, the race leader. Both mushers immediately began an eight-hour mandatory layover before the final run to the finish line in Nome, the far-flung town in Western Alaska, popular these days for the backdrop to Discovery Channel's "Bering Sea Gold."

Zirkle, who hails from Two Rivers, Alaska, quickly closed the gap on Seavey during the 46-mile run from the village of Elim to White Mountain. Despite leaving hours behind Seavey, Zirkle took less rest in Elim and charged through the hilly terrain between the two checkpoints.

Seavey was noticeably more subdued coming into the checkpoint early Tuesday. He looked groggy, his face and moustache covered with ice. He moved slowly as he parked his dogs and laid out straw. The Sterling musher said his dogs were tired coming into the checkpoint. Seavey said he never saw Zirkle during his run to White Mountain. Zirkle said she didn't see Seavey either.

READ MORE: It's Aliy vs. Mitch, a duel in the sun to glory in Nome