Zigzag Glacier is an

alpine glacier A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as ...

located on the upper southwest slopes of

Mount Hood Mount Hood is a potentially active stratovolcano in the Cascade Volcanic Arc. It was formed by a subduction zone on the Pacific coast and rests in the Pacific Northwest region of the United States. It is located about east-southeast of Portlan ...

in the U.S. state of

Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...

. It ranges in elevation from with fingers in canyons extending to about , and lies almost entirely within

Mount Hood Wilderness The Mount Hood Wilderness is a protected wilderness area inside the Mount Hood National Forest, in the U.S. state of Oregon. The area, covering , includes the peak of Mount Hood and its upper slopes, and ranges from temperate rain forests at the l ...

. The upper extent is divided from Reid Glacier by Illumination Rock. The top of the glacier is at the foot of Crater Rock. The glacier is bounded on the east by a slight rise shared with the

Palmer Glacier Palmer Glacier is a glacier on the south slopes of Mount Hood in the U.S. state of Oregon. The glacier is situated at an elevation range of , and was named for Joel Palmer, an Oregon pioneer. Palmer Glacier is the most well-known of the twelve g ...

(a popular skiing area north of

Timberline Lodge Timberline Lodge is a mountain lodge on the south side of Mount Hood in Clackamas County, Oregon, about east of Portland. Constructed from 1936 to 1938 by the Works Progress Administration, it was built and furnished by local artisans during the ...

since the 1930s) and on the northwest by Reid Glacier. It is the source of the

Zigzag River The Zigzag River is a tributary, about long, of the Sandy River in the U.S. state of Oregon. The Zigzag and one of its major tributaries, the Little Zigzag River, drain the Zigzag Glacier on Mount Hood, a high volcanic peak in the Cascade Ra ...

which has

eroded Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust, and then sediment transport, tra ...

a large, steep

canyon A canyon (from ; archaic British English spelling: ''cañon''), or gorge, is a deep cleft between escarpments or cliffs resulting from weathering and the erosion, erosive activity of a river over geologic time scales. Rivers have a natural tenden ...

named Zigzag Canyon. Below the glacier, its

snowfield A snow field, snowfield or neve is an accumulation of permanent snow and ice, typically found above the snow line, normally in mountainous and glacial terrain. Glaciers originate in snowfields. The lower end of a glacier is usually free from sn ...

varies significantly seasonally, varying in length by almost two miles (3.2 km). In 1922, a

jökulhlaup A jökulhlaup ( ) (literally "glacial run") is a type of glacial outburst flood. It is an Icelandic term that has been adopted in glaciological terminology in many languages. It originally referred to the well-known subglacial outburst flood ...

originating from Zigzag Glacier as a flow of dark debris came out of a crevasse high on the glacier. It flowed on the surface more than 650 m (2100 ft) before entering another crevasse, and precipitated a minor panic by those who thought Mount Hood was erupting.

References

Glaciers of Mount Hood Glaciers of Clackamas County, Oregon Mount Hood National Forest Glaciers of Oregon {{ClackamasCountyOR-geo-stub

See also

References