Seavey, who set a course record in 2017, was the first to leave the checkpoint at the village of Nikolai, 263 miles into the 988-mile race. He had 14 of his 16 dogs remaining.

Hot on Seavey's heels were Norway's Joar Lefiseth Ulsom and Wasilla's Ryan Redington, who had led earlier in the race. Redington's grandfather, Joe Redington Sr., was one of the founders of the race.

Farther back in the pack, mushers were complaining of temperatures that they said were too warm. Measurement devices read 32 degrees Fahrenheit, and some mushers had yet to get out of their sleeping bags, reclining on straw next to their dogs at required rest stop. (Four-time champ Jeff King reported to race staff that he had not yet put on his mittens.)

Not enough cold weather can melt ice and snow, creating slush that can slow down dogs and sleds and sometimes create hazards that mushers would not otherwise encounter.

Two mushers have pulled out, including 64-year-old crowd favorite Dee Dee Jonrowe, who was competing in her 36th and last Iditarod.