The Three Sisters are closely spaced volcanic peaks in the U.S. state of Oregon. They are part of the Cascade Volcanic Arc, a segment of the Cascade Range in western North America extending from southern British Columbia through Washington and Oregon to Northern California. Each more than 10,000 feet (3,000 m) in elevation, they are the third-, fourth- and fifth-highest peaks in Oregon. Located in the Three Sisters Wilderness at the boundary of Lane and Deschutes counties and the Willamette and Deschutes national forests, they are about 10 miles (16 km) south of the nearest town, Sisters. Diverse species of flora and fauna inhabit the area, which is subject to frequent snowfall, occasional rain, and extreme temperature variation between seasons. The mountains, particularly South Sister, are popular destinations for climbing and scrambling.
Ptarmigan Traverse is an alpine climbing route in the North Cascades of Washington State. The route, from Cascade Pass to Dome Peak, is generally remote, unmarked, and challenging, traversing rugged terrain and several glaciers.
Park Glacier is located on the northeast slopes of Mount Baker in the North Cascades of the U.S. state of Washington. Park Glacier descends to the Park Cliffs along its eastern margin while the northern tongue of the glacier descends to nearly 4,500 ft (1,400 m) and is below Park Cliffs and Lava Divide. In the middle of its course, Park Glacier is connected to Rainbow Glacier to the north and Boulder Glacier to the south.
Rainbow Glacier is located on the northeast slopes of Mount Baker in the North Cascades of the U.S. state of Washington. Rainbow Glacier descends to nearly 4,500 ft (1,400 m) to the north of Lava Divide. In the middle of its course, Rainbow Glacier is connected to Park Glacier to its south and Mazama Glacier to the west. Between 1850 and 1950, Rainbow Glacier retreated 4,494 ft (1,370 m). During a cooler and wetter period from 1950 to 1979, the glacier advanced 1,679 ft (512 m) but between 1980 and 2006 retreated back 1,345 ft (410 m).
Roosevelt Glacier is located on the north slopes of Mount Baker in the North Cascades of the U.S. state of Washington. Roosevelt Glacier descends to nearly 5,000 ft (1,500 m) at Chromatic Moraine. In the middle of its course, Roosevelt Glacier is connected to Coleman Glacier to its south.
Neve Glacier is in North Cascades National Park in the U.S. state of Washington and is on the north slopes of Snowfield Peak. Neve Glacier flows generally north and splits in two with two terminal tongues, one flowing to the northwest which is known as Ladder Creek Glacier and the other descending a total of more than 1.8 mi (2.9 km) to the east. Ladder Creek Glacier descends from 7,800 to 6,000 ft, while the east tongue also originates from the same altitude and descends to 5,600 ft (1,700 m). Between 1850 and 2006, Neve Glacier is estimated to have retreated more than 1,000 m (3,300 ft).
Crystal Glacier is in North Cascades National Park in the U.S. state of Washington, on the south slopes of Mount Shuksan. Descending 1.25 mi (2.01 km) from just east of the summit of Mount Shuksan, near its origination point, Crystal Glacier is connected to the larger Sulphide Glacier to the west. Crystal Glacier descends from 8,200 to 5,800 ft, and is also connected to East Nooksack Glacier as well as Hanging Glacier near it uppermost margins. Both Crystal and Sulphide Glaciers have a series of 300-to-1,000-foot high cascades which are collectively referred to as Sulphide Basin Falls. Below these cascades lies Sulphide Lake, which empties over Sulphide Creek Falls, one of the highest waterfalls in North America with a nearly 2,200 ft (670 m) drop.
Spider Glacier is in Wenatchee National Forest in the U.S. state of Washington and is to the north of Spider Mountain. Spider Glacier is .30 mi (0.48 km) long and extends for .90 mi (1.45 km) across the north face of Spider Mountain. Spider Glacier is separated by an arête from Middle Cascade Glacier to the west.
Hidden Creek Glacier is in North Cascades National Park in the U.S. state of Washington and is on the northwest slope of Hagan Mountain. Retreat of this glacier from 1979 to 2005 exposed several rock outcroppings in the middle of the glacier. The terminus of Hidden Creek Glacier only retreated 50 m (160 ft) between 1979 and 2011, however the increase in area of exposed rock outcroppings in the middle of the glacier indicates rapid thinning.
Daniel Glacier is in Wenatchee National Forest in the U.S. state of Washington and is on the north slope of Mount Daniel. Daniel Glacier retreated almost 500 m (1,600 ft) between 1950 and 2005. Daniel Glacier is separated from Lynch Glacier to the west by a ridge.
Foss Glacier is within the Alpine Lakes Wilderness of Snoqualmie National Forest in the U.S. state of Washington and is on the northeast slope of Mount Hinman. Foss Glacier retreated almost 500 m (1,600 ft) between 1950 and 2005. Foss Glacier is separated from the nearly vanished Hinman Glacier to the west by a ridge.
Ladder Creek Glacier is in North Cascades National Park in the U.S. state of Washington and is a northwest tongue of the larger Neve Glacier. Ladder Creek Glacier added 105 m (344 ft) between 1950 and 1979, but lost 190 m (620 ft) from 1979 to 2006. Ladder Creek Glacier descends from 7,800 to 6,000 ft.
Noisy Creek Glacier is in North Cascades National Park in the U.S. state of Washington, .50-mile (0.80 km) northwest of Bacon Peak. Noisy Creek Glacier has retreated and left behind a series of small proglacial lakes. Noisy Creek Glacier descends from 6,400 to 5,800 ft. A ridge separates Noisy Creek Glacier from Green Lake Glacier to the east. The National Park Service is currently studying Noisy Creek Glacier as part of their glacier monitoring project.
Watson Glacier is in Snoqualmie National Forest in the U.S. state of Washington, on the north slope of Mount Watson. Watson Glacier retreated 430 ft (130 m) between 1950 and 2007 and is now only 1,150 ft (350 m) in length. Watson Glacier descends from 6,000 to 5,700 ft.
Redoubt Glacier is in North Cascades National Park in the U.S. state of Washington, on the east slopes of Mount Redoubt. Redoubt Glacier descends from the 8,400-foot (2,600 m) point on the east slope of Mount Redoubt then has a south terminus near 7,200 ft (2,200 m). The glacier then has a shallow gradient for most of its course before descending north on a wide 1.5 mi (2.4 km) front to 6,500 ft (2,000 m). Melt from the glacier feeds into Depot Creek which flows into Chilliwack Lake. The Depot Glacier lies to the west of Redoubt Glacier.
West Depot Glacier is in North Cascades National Park in the U.S. state of Washington, on the north slopes of Mount Redoubt. Depot Glacier descends from 7,400 to 5,900 ft. Melt from the glacier feeds into Depot Creek which flows into Chilliwack Lake. A ridge separates West Depot Glacier from Depot Glacier to the east.
S Glacier is in North Cascades National Park in the U.S. state of Washington, on the east slopes of Hurry-up Peak. S Glacier is disconnected in several spots. The uppermost sections terminate in icefalls, while the lower section ends in talus. Total descent of the glacier is from 7,600 to 5,500 ft. Yawning Glacier lies .75 mi (1.21 km) to the north.
Yawning Glacier is in North Cascades National Park in the U.S. state of Washington, on the east slopes of Magic Mountain. Yawning Glacier descends from 6,800 to 6,200 ft. S Glacier lies .75 mi (1.21 km) to the south and Cache Col Glacier is 1 mi (1.6 km) to the northwest.
Cache Col Glacier is in North Cascades National Park in the U.S. state of Washington, on the east slope of Mix-up Peak. Cache Col Glacier retreated nearly 100 m (330 ft) between 1950 and 2005. Cache Col Glacier is 1 mi (1.6 km) northwest of Yawning Glacier.
Mount Formidable is a mountain in the North Cascades of Skagit County, in Washington state. Its first ascent was undertaken by members of the original Ptarmigan Traverse, and the peak is a popular climb for parties on the traverse. It was named by early mountaineer Herman Ulrichs in 1935 because of the rugged appearance of its north face. The peak is usually accessed from Cascade Pass via the Ptarmigan Traverse.
