Volcano Information

    Mount Rainier
    Volcanic Alert Level: NORMAL Aviation Color Code: GREEN

    • Status: Mount Rainier is monitored by the Cascade Volcano Observatory and is at a background level of activity.
    • Volcanic History Overview: Mount Rainier, at 4392 m the highest peak in the Cascade Range, forms a dramatic backdrop to the Puget Sound region. Large Holocene mudflows from eruptions and from collapse of this massive, heavily glaciated andesitic volcano have reached as far as the Puget Sound lowlands. The present summit was constructed within a large crater breached to the east during a mid-Holocene eruption including the collapse of a once-higher edifice. More than a dozen postglacial tephras have been erupted from Mount Rainier. The last magmatic eruption of Mount Rainier was about 1000 years ago. Extensive hydrothermal alteration of the upper portion of the volcano has contributed to its structural weakness. An active thermal system has produced an elaborate system of steam caves in the summit icecap.
    • Location: Western US, WA

      Latitude: 46.853
      Longitude: -121.76
      Elevation: 4392 m

      Recent Eruption: Possibly in 1894 and 1840's, larger eruption certain 1,000 years ago
    • Hazard Assessments: Hoblitt, et.al., 1998, Volcano Hazards from Mount Rainier, Washington, Revised 1998, USGS Open-File Report 98-428.
    • Link to monitoring data: The Pacific Northwest Seismic Network