Update 2:45 p.m. - Denali Park musher Jeff King has scratched in Pelly Crossing, according to the Yukon Quest website. According to the Quest, "King initially left Pelly and got as far as Stepping Stone, but made the decision to scratch. After a lengthy rest, King cited concern with the amount of dog food needed to travel the distance to Dawson City at these extreme temperatures."

Update 2 p.m. - Brent Sass has arrived in Dawson. 

FAIRBANKS - The lead mushers in the Yukon Quest International Sled Dog Race are expected to arrive at the halfway point in Dawson City today.

Brent Sass of Eureka was leading the field Tuesday morning, with the SpotTracker showing him with a strong lead. The first musher into Dawson who finishes the race also wins 4 ounces of placer gold. 

Mushers have a mandatory 24-hour rest in the old Klondike Gold Rush town, a rule change from previous years, which called for a 36-hour rest.

Sass was followed by Hugh Neff of Tok and Allen Moore of Two Rivers. 

Twenty-two of the original 26 mushers are still on the trail after four scratched, citing the well-being of their teams after a rough trail amid temperatures nearing 50 below zero. Temperatures in Dawson were reported to be minus 41 Tuesday morning.

Rookie Jason Campeau was penalized 8 hours after breaking a runner and borrowing a sled Yukon Quest 300 musher Jake Berkowitz, who scratched from the 300. Unlike in the Iditarod, where mushers are allowed to send out replacement sleds along the trail, Quest mushers are expected to use the same sled over the 1,000 mile course.

Kristin Knight Pace was the last musher to leave Pelly Crossing for the long trail to Dawson Tuesday at 11:50 a.m. Yukon time.

The SpotTracker also shows Jeff King off-route and heading back toward Pelly Crossing. Yukon Quest officials were in transit Tuesday and couldn't be reached for comment. This story will be updated.