As the Yukon Quest continues into its fourth day, reigning champion Brent Sass continues to hold a comfortable lead. As of Tuesday afternoon he was about 30 kilometres ahead of Allen Moore, who is still second in the race standings.

Both mushers are expected to reach the race's checkpoint at Dawson City on Wednesday. The official race tracker predicts Sass could arrive before lunchtime, and Moore sometime mid-afternoon.

Mushers must spend at least 36 hours in Dawson City, before beginning the second half of the 1,600 kilometre race to Whitehorse.

Last year, race officials reduced the mandatory layover time in Dawson to just 24 hours, but decided to revert back to a 36-hour stop this year.

Jessie Holmes

Jessie Holmes, from Nenana, Alaska, won the Yukon Quest 300 on Monday. (Yukon Quest)

Mushers Hugh Neff and Matt Hall were racing close together Tuesday afternoon, about 15 kilometres behind Allen Moore. Yukoner Ed Hopkins was still fifth in the standings, running about 25 kilometres back from Neff and Hall. They're all projected to reach Dawson City on Wednesday evening.

On Monday, a winner was crowned in the Yukon Quest 300, a shorter race that's often run by less-experienced mushers. Jessie Holmes, a rookie from Alaska, finished the 500 kilometre race in just over two days.

Aliy Zirkle placed second, and Joanna Jagow placed third in the Quest 300.