An elite group of runners, cyclists and cross-country skiers will test their resolve in the Susitna 100, a winter endurance race spanning 100 miles of Alaska's rugged wilderness terrain. Seventy-five racers compete in the Susitna 100 and another 125 tackle the Little Su 50K. The event brings endurance athletes from 11 states to Alaska; Italy, Canada, Germany and France will also be represented.

Racers will complete an out-and-back route that begins at the Point MacKenzie General Store outside of Wasilla, Alaska, a 1.5-hour drive north of Anchorage. Competitors will ski, bike or run through remote forests and across frozen waterways northwest to Alexander Lake, stopping only to grab a quick bite, change clothes, or wait out an unforeseen winter storm. Once they reach the lake, they turn around and begin the grueling 50-mile leg back to the start/finish line.

On the course, competitors must contend with Alaska s untamed winter. Drifting snow can bury geographic landmarks and most of the course is not accessible by road, even in summer. The course follows the frozen Susitna and Yentna Rivers, which serve as wintertime highways connecting rural Alaska. Racers occasionally encounter snowmobilers or dogsled teams along the rivers. Except for these chance encounters, and the occasional patrolling race official, competitors are on their own.

The Susitna 100 s roots trace back to several bike, ski, and snowshoe races along the Iditarod Trail in the 1980s and 1990s. The races were reorganized as the Susitna 100 in 1997.

For more on the Susitna 100, visit http://www.susitna100.com.