In one of the "Iron man," or perhaps "Iron dog," events of sled-dog racing, the 1,000-mile Yukon Quest race is under way, with 24 teams mushing from Fairbanks, Alaska, to Whitehorse in the Canadian Yukon. The trail follows historic Gold Rush and Mail Delivery routes from the turn of the 20th Century, and passes through part of Yukon-Charley Rivers National Preserve.

The race, dubbed "the toughest sled dog race in the world," takes the teams through the tiny outpost of Slaven's Roadhouse in Yukon-Charley, where the mushers take a break before pushing on eastward. According to the National Park Service:

The real origins of mushing out of Interior Alaska, along the Yukon, and into Canada date back much farther in history. The trail that today’s race follows traces routes followed by prospectors, mail carriers, and commercial suppliers in the late 1800s and well into the next century. More than 100 miles of the race goes through Yukon-Charley National Preserve, which straddles the Yukon River downstream of Eagle.

Mushers and their teams must demonstrate the ability to succeed in a long distance race by completing qualifying races. Between Fairbanks and Whitehorse, mushers pass through nine checkpoints. Three locations are set up as “dog drop” locations, where dogs can be left in the care of others who will get them safely back to the mushers at the end of the race. One of the dog drops is at Slaven’s Roadhouse, a historic landmark along the Yukon River now operated by the staff of Yukon-Charley Rivers National Preserve. The staff works with volunteers to help feed mushers, and provide a warm place to rest and sleep, and care for their dogs.

...While support teams such as those at Slaven’s can provide warm respite from the trail, mushers must deal with the same conditions that historically faced winter travelers in the north: temperatures to 40 below, high winds, occasional open water on the Yukon, ice and other rough trail conditions, and the fatigue that builds during the long hours of solitary travel.

There's a $150,000 purse in the race, with the winner receiving $28,395.

In case you're wondering, the the Yukon Quest has 11 checkpoints whereas the Iditarod has 26, making the distances between checkpoints longer, on average, in the Yukon Quest, and requiring Yukon Quest mushers to camp along trail significantly more often than in Iditarod and to pack their sleds more heavily. Plus, the route of the Yukon Quest takes the teams over four mountain ranges, vs. one for the Iditarod.

When teams reach Dawson City later this week, possibly as soon as Thursday, they'll have to take a mandatory 36-hour break to rest their dogs. The leading mushers are expected to reach Whitehorse by February 19.