The White River National Forest Service has given final approval to a now 4-year-old proposal to expand Arapahoe Basin’s expert and intermediate terrain.

The 958-acre ski area will add a new lift and 338 acres of intermediate bowl skiing and expert cliffs and chutes in an area known as the Beavers and Steep Gullies. The project will mark the largest expansion since Arapahoe Basin nearly doubled in size in 2007 with a push into 400 acres of Montezuma Bowl.

The Forest Service’s Record of Decision allows Arapahoe Basin to add a new surface lift accessing Montezuma Bowl, replace both the Molly Hogan and Pallavicini chairlifts, remove the Norway lift and build ziplines for an aerial adventure tour and challenge course.

“The decision will enhance both the winter and summer recreation opportunities at A-Basin,” White River National Forest Supervisor Scott Fitzwilliams said in a statement. “Lift replacements and grading will improve the quality of experience for skiers and snowboarders. Additionally, the summer aerial activity will reach a wide audience and provide experiences for an increasingly diverse recreating public.”

The plan drew six objections, far fewer than recent expansion plans proposed by nearby Breckenridge. The draft environmental review the agency issued in February gleaned about 100 comments, most of those from users who wanted to see the ski area grow.

The White River, the most trafficked national forest in the nation which hosts more than 7 million user days at 11 major ski areas, requires each ski area to a craft master plans mapping future growth. The 2012 master plan at Arapahoe Basin asked to grow inside its special-use boundary, which zones both the Beavers and Steep Gullies for lift-served skiing. The ski area wants to mitigate avalanche danger in the region, where six skiers have died in avalanches since 1982.

The White River National Forest’s 2002 management plan outlines support for ski area expansions where demand warrants that growth. Demand at Arapahoe Basin has soared in the last decade, with the area posting record visitation and revenues in recent years