Last season, Arapahoe Basin opened 468 acres of new terrain. Nearly 340 of those make up an area of intermediate to advanced runs called the Beavers, which is now served by a four-person chairlift. But the remaining 129 acres, known collectively as the Steep Gullies, are intended for experts only and comprise the most challenging skiing at A-Basin. All of the narrow chutes have sharp pitches and are designated double-black-diamond runs. But don't let that intimidate you: The Steep Gullies also has some of the most un-tracked snow on the mountain, mainly because all the runs empty out onto an access road, requiring skiers and snowboarders to make the long hike back to the Pallavicini lift.