Reid Glacier is an alpine glacier located on the west slope of Mount Hood

Mount Hood

Mount Hood, called Wy'east by the Multnomah tribe, is a stratovolcano in the Cascade Volcanic Arc of northern Oregon. It was formed by a subduction zone and rests in the Pacific Northwest region of the United States...

 in the U.S. state

U.S. state

A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

 of Oregon

Oregon

Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...

. It ranges in elevation from about 6,000 to 9,800 ft (1,800 to 3,000 m). The glacier is the source of the Sandy River

Sandy River (Oregon)

The Sandy River is a tributary of the Columbia River in northwestern Oregon in the United States. Measured by a United States Geological Survey gauge downstream of the Sandy's confluence with the Bull Run River, from the mouth, the river's average discharge is . The maximum daily recorded flow...

. The upper extent of the glacier is known for extensive crevasse

Crevasse

A crevasse is a deep crack in an ice sheet rhys glacier . Crevasses form as a result of the movement and resulting stress associated with the sheer stress generated when two semi-rigid pieces above a plastic substrate have different rates of movement...

s.

The glacier is a remnant of the massive glaciers that formed during the last ice age

Ice age

An ice age or, more precisely, glacial age, is a generic geological period of long-term reduction in the temperature of the Earth's surface and atmosphere, resulting in the presence or expansion of continental ice sheets, polar ice sheets and alpine glaciers...

. It is bounded on the north by Yokum Ridge which also defines the southern side of Sandy Glacier

Sandy Glacier

Sandy Glacier is an alpine glacier located on the west slope of Mount Hood in the U.S. state of Oregon. It extends in elevation from about . The glacier is the source of Muddy Fork, a tributary of the Sandy River. The upper extent of the glacier is known for extensive crevasses.The glacier is a...

, and by a ridge on the south bounding the north side of Zigzag Glacier

Zigzag Glacier

The Zigzag Glacier is an alpine glacier located on the upper southwest slopes of Mount Hood in the U.S. state of Oregon.It ranges in elevation from 7,200 to 10,200 ft with fingers in canyons extending to about 6,400 ft , and lies almost entirely within Mount Hood Wilderness. The upper...

. The eastern and upper reaches of this ridge include Illumination Rock. The uppermost portion of the glacier is below Leuthold Couloir

Couloir

A couloir is a narrow gully with a steep gradient in a mountainous terrain. A couloir may be a seam, scar, or fissure, or vertical crevasse in an otherwise solid mountain mass...

. The glacier lies entirely within Mount Hood Wilderness

Mount Hood Wilderness

The Mount Hood Wilderness is a protected wilderness area inside the Mount Hood National Forest which is located 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 lower elevations, to glaciers and...

.

The Reid Glacier has decreased in area by 35% between 1907 and 2004. The glacier terminus

Glacier terminus

A glacier terminus, or snout, is the end of a glacier at any given point in time. Although glaciers seem motionless to the observer, in reality glaciers are in endless motion and the glacier terminus is always either advancing or retreating...

has retreated by 1607 feet (489.8 m) over the same time period.