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Photo of this volcano
  • Country
  • Primary Volcano Type
  • Last Known Eruption
  • 44.332°N
  • 121.837°W

  • 2376 m
    7795 ft

  • 322807
  • Latitude
  • Longitude

  • Summit

  • Volcano

The Global Volcanism Program has no activity reports for Washington.

The Global Volcanism Program has no Weekly Reports available for Washington.

The Global Volcanism Program has no Bulletin Reports available for Washington.

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.

Eruptive History

The Global Volcanism Program is not aware of any Holocene eruptions from Washington. If this volcano has had large eruptions (VEI >= 4) prior to 10,000 years ago, information might be found on the Washington page in the LaMEVE (Large Magnitude Explosive Volcanic Eruptions) database, a part of the Volcano Global Risk Identification and Analysis Project (VOGRIPA).

Deformation History

There is no Deformation History data available for Washington.

Emission History

There is no Emissions History data available for Washington.

Photo Gallery

Mount Washington, reflected here in Big Lake on its NW side, is a Pleistocene shield volcano deeply dissected by glaciers. Erosion has exposed many dikes in the summit cone, which has not erupted since the late Pleistocene. Vents on the NE flank, behind the ridge on the left, erupted about 1300 years ago, probably as part of a a fissure-fed eruption at Blue Lake Crater.

Photo by Lee Siebert, 1995 (Smithsonian Institution).
The sharp-topped pinnacle of Mount Washington, seen here from east of Santiam Pass on its NE, is a lava plug that caps a heavily eroded shield volcano. The steep-sided lava plug forming the summit was the last major Oregon peak to be climbed, resisting ascent until 1923.

Photo by Lee Siebert, 1982 (Smithsonian Institution).
The dramatic summit pinnacle of Mount Washington is a central lava plug that caps a shield volcano. Mount Washington has been extensively dissected by glacial erosion, revealing the inner structure of the volcano. Fresh lava flows from cinder cones near North Sister volcano appear in the foreground of this view from the SE.

Photo by Lee Siebert, 1995 (Smithsonian Institution).
Early morning alpenglow gilds the summit of Mount Washington, one of the most distinctive landmarks of the central Oregon Cascades. Mount Washington is an extensively eroded basaltic shield volcano capped by a steep-sided central plug. The central edifice has not been active since the late Pleistocene, but a series of small spatter cones on its NE flank about 4 km from the summit erupted some 1300 years ago.

Photo by Lee Siebert, 1995 (Smithsonian Institution).
Mount Washington, seen here from Black Butte to the SE, is an eroded Pleistocene shield volcano capped by a steep central lava plug. NE flank spatter cones were active about 1300 years ago. Fresh lava flows in the foreground of this photo originated from Belknap volcano and cinder cones near North Sister volcano.

Photo by Lee Siebert, 1995 (Smithsonian Institution).
The contrasting morphology of rounded Hayrick Butte on the left and flat-topped Hoodoo Butte on the right, north of Mount Washington in the central Oregon Cascades, reflects dramatic differences in their origin. Hoodoo Butte is a "tuya," a volcanic cone formed by eruptions that ponded in a cavity melted through a glacial ice sheet. Hayrick Butte formed slightly later, when the Pleistocene ice sheet had melted, and formed the classic rounded profile of a scoria cone.

Photo by Lee Siebert, 1995 (Smithsonian Institution).
Early spring snows linger on the dramatic spine of Mount Washington, seen here from the east, north of Santiam Pass. Washington is of several major Pleistocene Cascade volcanoes, including Mount Thielsen, North Sister, and Mount Jefferson, whose resistant central conduit has been exposed by erosion.

Photo by Lee Siebert, 2000 (Smithsonian Institution).
Blue Lake Crater in the foreground is one of three overlapping craters located east of Santiam Pass. The craters formed about 1,300 years ago during explosions through older volcanic bedrock; a chain of spatter cones about 6 km SSW of Blue Lake may have been active during the same eruption. The snow-covered summit of Pleistocene Mount Washington is visible in the background.

Photo by Lee Siebert, 1999 (Smithsonian Institution).
GVP Map Holdings

The maps shown below have been scanned from the GVP map archives and include the volcano on this page. Clicking on the small images will load the full 300 dpi map. Very small-scale maps (such as world maps) are not included. The maps database originated over 30 years ago, but was only recently updated and connected to our main database. We welcome users to tell us if they see incorrect information or other problems with the maps; please use the Contact GVP link at the bottom of the page to send us email.

Smithsonian Sample Collections Database

There are no samples for Washington in the Smithsonian's NMNH Department of Mineral Sciences Rock and Ore collection.

External Sites