46.206 N, 121.490 W
summit elevation 3742 m
Mt Adams is located 50 km east of Mt St Helens volcano. The volcano consists of several overlapping cones, and is the second largest of the Cascade stratovolcanoes. The flat summit was formed as the result of several cone building eruptions.
The upper region of Mount Adams consists of glaciers, barren moraines, and alpine meadows. Below an elevation of 2000 m, most of the volcano is covered in dense forest. The summit contains an icecap, and the flanks have ten glaciers.
The villages of Trout Lake and Glenwood are the only settlements near the volcano. During the summer, there are many climbers and campers on the mountain. The nearest large population centres are Yakima (85 km NE), Goldendale (65 km SE), White Salmon-Hood River (55 km S), and Portland-Vancouver (100 km SW).
Lava flows are visible extending 10 km from the volcano. The most recent eruption 1000 years ago produced tephra fall and a small lava flow. Postglacial lava
flows have occurred from nine vents.
A large debris-avalanche deposit located high on the southwest side of the summit, formed 5100–5300 years ago. Trout Lake Mudflow moved 60 km from the source, in a single event.
A study of postglacial activity suggests future eruptions may occur as strombolian, phreatomagmatic, or phreatic. A future large sector collapse of the main cone, would produce a catastrophic debris flow along the affected drainage.
Eruptions of Mt Adams Volcano
Mount Adams has not erupted for 1000 years. Between 1000 and 15 000 years ago, eruptions were infrequent, relatively small, and mainly effusive.