The Hardrock 100 is considered one of the toughest ultramarathons on Earth. Held each summer in the San Juan Mountains of Colorado, it challenges endurance athletes to cover 100 very tough miles (160 km) as quickly as they can. It is a difficult trail to run, even in the best of conditions, and no one has ever attempted to cross it in the winter. That is, until now. In this short documentary film we join ultrarunner Jason Schlarb as he attempts that very thing. In brutal conditions he sets off to test himself on the Hardrock trail in January, when swirling winds, deep snow, and cold temperatures are at their worst. Does he make it? You’ll just have to watch the video below to find out.