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Adams

Photo of this volcano
  • Country
  • Landform (Volc Type)
  • Last Known Eruption
  • 46.206°N
  • 121.49°W

  • 3742 m
    12277 ft

  • 321040
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number


Most Recent Bulletin Report: September 1997 (BGVN 22:09) Citation IconCite this Report

Avalanche moves 5 km down the uninhabited east flank on 20 October

A sizable rock avalanche occurred during 20 October on the E side of Mount Adams. Based on seismic signals, the avalanche began at 0031 and lasted about six minutes. There were no seismic precursors.

On 21 October, a US Geological Survey scientist inspected the avalanche deposit from a small airplane. The avalanche originated at ~3,500 m elevation on the S face of The Castle, a prominent topographic knob at the head of Battlement Ridge. The source area formed an obvious, near-vertical scar roughly triangular in shape with sides ~300 m long. The summit of The Castle remained intact. The avalanche descended the Klickitat Glacier icefall and left a thin veneer of rock debris on the steep upper part of the glacier. Below ~2,500 m elevation the deposit thickened. The avalanche traveled beyond the end of the Klickitat Glacier and continued ~2 km down the valley of Big Muddy Creek, a Klickitat River tributary. The length of the avalanche track totaled ~5 km, and the width may exceed 1 km in places. The average width is ~0.5 km. Maximum deposit thickness may exceed 20 m. The volume of the avalanche debris is probably between 1 and 5 million m3.

The avalanche deposit temporarily blocked the flow of Big Muddy Creek, resulting in the formation of a small lake on the avalanche debris. By noon on 21 October the avalanche dam had breached, and flow in Big Muddy Creek did not appear unusual. Continuing hazards exist due to the threat of additional rockfalls, damming and downstream flooding. However, these hazards exist primarily in unpopulated areas deep within the backcountry of Yakima Nation lands. No evidence suggests that hazards in populated areas far downstream have increased significantly.

This avalanche appeared unrelated to a similar-sized avalanche on the W flank of Mount Adams about seven weeks earlier (31 August). This earlier avalanche consisted of about 90% snow and ice; its source was Avalanche Glacier cirque at ~ 3,650-m elevation on the upper SW flank. Both avalanches originated where rocks evidently had been weakened by intense hydrothermal alteration. Both avalanches may have been triggered in part by wet subsurface conditions associated with late-season thawing of exceptionally heavy snowpack in conjunction with early-season storms. Neither avalanche was triggered by regional earthquake or volcanic activity.

After the 20 October avalanche, a second, smaller one swept down the same path and yielded a much smaller seismic signal that began at 0729 on 24 October. Preliminary reports suggested that the second avalanche traveled only about half the distance of the first.

Mount Adams, one of the largest volcanoes in the Cascade Range, dominates the Mount Adams volcanic field in Washington's Skamania, Yakima, Klickitat, and Lewis counties and the Yakima Indian Reservation of S-central Washington (1,250 km2). At Adams, large landslides and lahars that need not be related to eruptions probably pose the most destructive, far-reaching hazard.

Information Contacts: Cascades Volcano Observatory (CVO), U.S. Geological Survey, 5400 MacArthur Blvd., Vancouver, WA 98661, USA (URL: http://volcanoes.usgs.gov/); Geophysics Program, University of Washington, Seattle, WA 98195, USA (URL: https://volcanoes.usgs.gov/observatories/cvo/).

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

Bulletin Reports - Index

Reports are organized chronologically and indexed below by Month/Year (Publication Volume:Number), and include a one-line summary. Click on the index link or scroll down to read the reports.

09/1997 (BGVN 22:09) Avalanche moves 5 km down the uninhabited east flank on 20 October




Information is preliminary and subject to change. All times are local (unless otherwise noted)


September 1997 (BGVN 22:09) Citation IconCite this Report

Avalanche moves 5 km down the uninhabited east flank on 20 October

A sizable rock avalanche occurred during 20 October on the E side of Mount Adams. Based on seismic signals, the avalanche began at 0031 and lasted about six minutes. There were no seismic precursors.

On 21 October, a US Geological Survey scientist inspected the avalanche deposit from a small airplane. The avalanche originated at ~3,500 m elevation on the S face of The Castle, a prominent topographic knob at the head of Battlement Ridge. The source area formed an obvious, near-vertical scar roughly triangular in shape with sides ~300 m long. The summit of The Castle remained intact. The avalanche descended the Klickitat Glacier icefall and left a thin veneer of rock debris on the steep upper part of the glacier. Below ~2,500 m elevation the deposit thickened. The avalanche traveled beyond the end of the Klickitat Glacier and continued ~2 km down the valley of Big Muddy Creek, a Klickitat River tributary. The length of the avalanche track totaled ~5 km, and the width may exceed 1 km in places. The average width is ~0.5 km. Maximum deposit thickness may exceed 20 m. The volume of the avalanche debris is probably between 1 and 5 million m3.

The avalanche deposit temporarily blocked the flow of Big Muddy Creek, resulting in the formation of a small lake on the avalanche debris. By noon on 21 October the avalanche dam had breached, and flow in Big Muddy Creek did not appear unusual. Continuing hazards exist due to the threat of additional rockfalls, damming and downstream flooding. However, these hazards exist primarily in unpopulated areas deep within the backcountry of Yakima Nation lands. No evidence suggests that hazards in populated areas far downstream have increased significantly.

This avalanche appeared unrelated to a similar-sized avalanche on the W flank of Mount Adams about seven weeks earlier (31 August). This earlier avalanche consisted of about 90% snow and ice; its source was Avalanche Glacier cirque at ~ 3,650-m elevation on the upper SW flank. Both avalanches originated where rocks evidently had been weakened by intense hydrothermal alteration. Both avalanches may have been triggered in part by wet subsurface conditions associated with late-season thawing of exceptionally heavy snowpack in conjunction with early-season storms. Neither avalanche was triggered by regional earthquake or volcanic activity.

After the 20 October avalanche, a second, smaller one swept down the same path and yielded a much smaller seismic signal that began at 0729 on 24 October. Preliminary reports suggested that the second avalanche traveled only about half the distance of the first.

Mount Adams, one of the largest volcanoes in the Cascade Range, dominates the Mount Adams volcanic field in Washington's Skamania, Yakima, Klickitat, and Lewis counties and the Yakima Indian Reservation of S-central Washington (1,250 km2). At Adams, large landslides and lahars that need not be related to eruptions probably pose the most destructive, far-reaching hazard.

Information Contacts: Cascades Volcano Observatory (CVO), U.S. Geological Survey, 5400 MacArthur Blvd., Vancouver, WA 98661, USA (URL: http://volcanoes.usgs.gov/); Geophysics Program, University of Washington, Seattle, WA 98195, USA (URL: https://volcanoes.usgs.gov/observatories/cvo/).

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

There is data available for 15 confirmed Holocene eruptive periods.

0950 (?) Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode East flank?, Tephra layer 24
0950 (?) - Unknown Evidence from Correlation: Tephrochronology

List of 4 Events for Episode 1 at East flank?, Tephra layer 24

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava flow Uncertain
   - - - -    - - - - Ash
0950
(?)
   - - - - VEI (Explosivity Index)

0200 (?) Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode Tephra layer 23
0200 (?) - Unknown Evidence from Correlation: Tephrochronology

List of 5 Events for Episode 1 at Tephra layer 23

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Phreatic activity
   - - - -    - - - - Ash
   - - - -    - - - - Lapilli
   - - - -    - - - - Scoria
0200
(?)
   - - - - VEI (Explosivity Index)

0300 BCE (?) Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode Tephra layer 22
0300 BCE (?) - Unknown Evidence from Correlation: Tephrochronology

List of 3 Events for Episode 1 at Tephra layer 22

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Phreatic activity
   - - - -    - - - - Ash
0300 BCE
(?)
   - - - - VEI (Explosivity Index)

0400 BCE (?) Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode Tephra layer 21
0400 BCE (?) - Unknown Evidence from Correlation: Tephrochronology

List of 3 Events for Episode 1 at Tephra layer 21

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Ash
0400 BCE
(?)
   - - - - VEI (Explosivity Index)

0550 BCE ± 1000 years Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode Tephra layers 19-20
0550 BCE ± 1000 years - Unknown Evidence from Correlation: Tephrochronology

List of 5 Events for Episode 1 at Tephra layers 19-20

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Phreatic activity
   - - - -    - - - - Ash
   - - - -    - - - - Lapilli
   - - - -    - - - - Scoria Uncertain
0550 BCE ± 1000 years    - - - - VEI (Explosivity Index)

1850 BCE (after) Confirmed Eruption Max VEI: 1 (?)

Episode 1 | Eruption Episode SSE flank (2100 m)
1850 BCE (after) - Unknown Evidence from Correlation: Tephrochronology

List of 4 Events for Episode 1 at SSE flank (2100 m)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava flow
   - - - -    - - - - Scoria
1850 BCE
(after)
   - - - - VEI (Explosivity Index)

2650 BCE ± 300 years Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode Tephra layers 17-18
2650 BCE ± 300 years - Unknown Evidence from Correlation: Tephrochronology

List of 4 Events for Episode 1 at Tephra layers 17-18

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Phreatic activity
   - - - -    - - - - Ash
   - - - -    - - - - Lapilli
2650 BCE ± 300 years    - - - - VEI (Explosivity Index)

2950 BCE ± 100 years Confirmed Eruption Max VEI: 1 (?)

Episode 1 | Eruption Episode SSE flank (2600 m), Tephra layer 16
2950 BCE ± 100 years - Unknown Evidence from Correlation: Tephrochronology

List of 5 Events for Episode 1 at SSE flank (2600 m), Tephra layer 16

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava flow
   - - - -    - - - - Ash
   - - - -    - - - - Scoria
2950 BCE ± 100 years    - - - - VEI (Explosivity Index)

3250 BCE ± 300 years Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode Tephra layer 15
3250 BCE ± 300 years - Unknown Evidence from Correlation: Tephrochronology

List of 5 Events for Episode 1 at Tephra layer 15

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Phreatic activity
   - - - -    - - - - Ash
   - - - -    - - - - Lapilli
   - - - -    - - - - Scoria
3250 BCE ± 300 years    - - - - VEI (Explosivity Index)

3550 BCE (?) Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode Tephra layer 14
3550 BCE (?) - Unknown Evidence from Correlation: Tephrochronology

List of 4 Events for Episode 1 at Tephra layer 14

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Ash
   - - - -    - - - - Pumice
3550 BCE
(?)
   - - - - VEI (Explosivity Index)

3800 BCE ± 1950 years Confirmed Eruption Max VEI: 1 (?)

Episode 1 | Eruption Episode NNE flank (2100-2250 m)
3800 BCE ± 1950 years - Unknown Evidence from Correlation: Tephrochronology

List of 4 Events for Episode 1 at NNE flank (2100-2250 m)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava flow
   - - - -    - - - - Scoria
3800 BCE ± 1000 years    - - - - VEI (Explosivity Index)

4050 BCE ± 500 years Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode Upper SW flank?, Tephra layers 11-13
4050 BCE ± 500 years - Unknown Evidence from Correlation: Tephrochronology

List of 7 Events for Episode 1 at Upper SW flank?, Tephra layers 11-13

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Phreatic activity
   - - - -    - - - - Avalanche
   - - - -    - - - - Ash
   - - - -    - - - - Lapilli
   - - - -    - - - - Lahar or Mudflow
   - - - -    - - - - Edifice Destroyed Collapse/avalanche
4050 BCE ± 500 years    - - - - VEI (Explosivity Index)

4550 BCE (?) Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode NW flank (2200-2400 m), Tephra layer 10
4550 BCE (?) - Unknown Evidence from Correlation: Tephrochronology

List of 6 Events for Episode 1 at NW flank (2200-2400 m), Tephra layer 10

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava flow
   - - - -    - - - - Ash
   - - - -    - - - - Scoria
   - - - -    - - - - Pumice
4550 BCE
(?)
   - - - - VEI (Explosivity Index)

5150 BCE ± 500 years Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode Tephra layers 5-9
5150 BCE ± 500 years - Unknown Evidence from Correlation: Tephrochronology

List of 5 Events for Episode 1 at Tephra layers 5-9

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Ash
   - - - -    - - - - Lapilli
   - - - -    - - - - Scoria
5150 BCE ± 500 years    - - - - VEI (Explosivity Index)

7050 BCE ± 1000 years Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode Tephra layers 1-4
7050 BCE ± 1000 years - Unknown Evidence from Correlation: Tephrochronology

List of 4 Events for Episode 1 at Tephra layers 1-4

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Ash
   - - - -    - - - - Scoria
7050 BCE ± 1000 years    - - - - VEI (Explosivity Index)
Deformation History

There is no Deformation History data available for Adams.

Emission History

There is no Emissions History data available for Adams.

Photo Gallery

Mount Adams in the Cascade Range is seen here in 1981 from High Knob to the NW. Its base is at a lower elevation than its neighbor Mount Rainier and it has a larger volume. Numerous flank vents surround the volcano and a series of lava flows have erupted on the N, NW, S and E flanks.

Photo by Lee Siebert, 1981 (Smithsonian Institution).
Mount Adams is seen in this view from Mount St. Helens to the west. Eruptive activity continued into the Holocene from both summit and vents on the N, NW, S and E flanks.

Photo by Lee Siebert, 1979 (Smithsonian Institution).
Mount Adams is seen here beyond farmlands on the east side of the Cascades. Mount Adams, known to local tribes as Pahto or Klickitat, featured prominently in tribal legends. The summit was said to have been flattened by a mighty blow from its southern brother, Mount Hood (Wyeast), when the damsel St. Helens (La-wa-la-clough) preferred Adams over Hood.

Photo by Lee Siebert, 1982 (Smithsonian Institution).
The farmlands of the Trout Lake valley SW of Mount Adams are underlain by a massive lahar produced by collapse of the upper SW flank of Adams about 6,000 years ago. Altered rocks up to several meters in diameter that originated from near the summit of the volcano littered the surface of the deposit, which covered 15 km2 of the Trout Lake lowland and reached as far as 60 km to the south. The source of the mudflow was a debris avalanche from the upper White Salmon glacier area, just left of the shadow beneath the summit.

Photo by Lee Siebert, 1995 (Smithsonian Institution).
Adams Glacier descends from the summit of Mount Adams, seen here above Takhlakh Lake on the NW side. The main edifice was constructed primarily of lava flows during the Pleistocene, but flank vents produced lava flows and explosive eruptions during the Holocene. The Takh Takh Meadow lava flow originated from a vent low on the NW flank and traveled a total of 10 km, reaching several kilometers beyond the east (left) side of Takhlakh Lake.

Photo by Lee Siebert, 1981 (Smithsonian Institution).
Mount Adams in the southern Cascade Range of Washington in seen from the SW in this view. The large cirque below the left side of the summit is occupied by the White Salmon and Avalanche Glaciers and was the source of a large mudflow that traveled 60 km down the White Salmon River valley about 6,000 years ago.

Photo by Lee Siebert, 1995 (Smithsonian Institution).
This view of Mount Rainier from the NW shows neighboring Mount Adams to the right in 1985. The steep Willis Wall, named after the 19th-century geologist Bailey Willis, is to the left and exposes relatively young lava flows.

Photo by Lee Siebert, 1985 (Smithsonian Institution)
Mount Adams (lower right) and Mount Rainier are the two southernmost of a N-S-trending chain of large stratovolcanoes in the Cascade Range of Washington state. Adams Glacier can be seen descending to the SE from the summit icecap of Mount Adams in this aerial view from the south. The 1,250 km2 Mount Adams volcanic field contains numerous flank cones and lava flows, several of which erupted during the Holocene. Mount Rainier, Washington's highest peak, has been less active during the Holocene, but erupted during the 19th century.

Photo by Lee Siebert, 1980 (Smithsonian Institution).
GVP Map Holdings

Maps are not currently available due to technical issues.

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.

Smithsonian Sample Collections Database

The following 18 samples associated with this volcano can be found in the Smithsonian's NMNH Department of Mineral Sciences collections, and may be availble for research (contact the Rock and Ore Collections Manager). Catalog number links will open a window with more information.

Catalog Number Sample Description Lava Source Collection Date
NMNH 116133-1 Scoria -- --
NMNH 116133-2 Andesite -- --
NMNH 116133-3 Andesite -- --
NMNH 116133-4 Andesite -- --
NMNH 116133-5 Andesite -- --
NMNH 116133-6 Andesite -- --
NMNH 116133-7 Basalt (?) -- --
NMNH 116133-8 Scoria POTATO HILL --
NMNH 117254-1 Eclogite -- --
NMNH 117254-10 Actinolite Schist -- --
NMNH 117254-2 Eclogite -- --
NMNH 117254-3 Eclogite -- --
NMNH 117254-4 Eclogite -- --
NMNH 117254-5 Eclogite -- --
NMNH 117254-6 Eclogite -- --
NMNH 117254-7 Eclogite -- --
NMNH 117254-8 Eclogite -- --
NMNH 117254-9 Eclogite -- --
External Sites