Denali National Park, Alaska, closed out its 2012 climbing season this week with one of its lowest summit rates in decades.

The last days were marked with the rescue of three Danish mountaineers following a Thursday avalanche, according to National Park Service officials.

During the season, a total of 1,223 summit attempts were made, and only 498 made it to the top, for a summit success of 40.7 percent. Park service officials said it was the second lowest summit rate in the last 25 years.

On Thursday, Danes Michael Pilegaard, 26 Mads Knudsen, 30, and Nicolai Bo Silver, 26, were evacuated from the 17,200-foot high camp on Denali’s West Buttress climbing route by the park’s contract A-Star B3 helicopter. Two had suffered leg injuries in an avalanche and were unable to walk.

The three had set out from the high camp on Sunday, July 22, for a summit attempt via a non-standard route up the Autobahn, the slope leading from high camp to Denali Pass. They had scouted the route variation the previous day because they were concerned about the high avalanche danger on the standard route. While approaching their intended route up the Autobahn, they triggered an avalanche at approximately 1 p.m.

The avalanche swept them from the 17,600-foot elevation several hundred feet down the slope to a point approximately 200 meters from their campsite. Pillegaard, who was relatively uninjured, was able to drag his two companions back to their campsite, where they waited for two days, hoping the injuries would respond to rest and treatment.

On Wednesday,after determining Knudsen and Bo Silver would not be able to walk, the trio called for assistance on an aviation radio, hoping to make contact with an aircraft providing scenic overflights of the mountain.

The park’s A-Star B3 helicopter, which was on assignment in Wrangell-St. Elias National Park, headed over for a  reconnaissance flight, and mountaineering ranger Kevin Wright dropped a bag from the helicopter containing communication devices, food, fuel, and a stove to the group.

Then on Thursday, Pilot Andy Hermansky flew to high camp site at 9 a.m. and retrieved the climbers in three trips. Knudsen and Bo Silver were evacuated via a rescue basket on the end of a 125-foot long line and the uninjured Pillegaard was loaded into the helicopter for the trips to Base Camp, according to National Park Service officials. The two injured climbers were met by LifeMed helicopters at Base Camp and flown to Mat Su Regional Hospital for treatment.