Title: The USGS Cascades Volcano Observatory - Research, monitoring, and the science of preparing society for low-probability, high-consequence events
What is the greatest hazard presented by Mount Rainier?
Debris flows (lahars) pose the greatest hazard to people near Mount Rainier. A debris flow is a mixture of mud and rock debris that looks and behaves like flowing concrete. Giant debris flows sometimes develop when large masses of weak, water-saturated rock slide from the volcano's flanks. Many of these debris flows cannot be predicted and may even occur independently of a volcanic eruption.
Giant debris flows can also form during an eruption as hot rock fragments tumble down the volcano's slopes, eroding and melting snow and glacier ice. Although they happen infrequently, giant debris flows have the potential to inundate much of the southern Puget Sound lowland. Scientists estimate that debris flows can travel the distance between Mount Rainier and the Puget Sound lowland in as little as 30 minutes to a few hours. About 100,000 people now live in areas that have been buried by debris flows during the past few thousand years.
During the past 10,000 years, about 60 giant debris flows from Mount Rainier have filled river valleys to a depth of hundreds of feet near the volcano, and have buried the land surface under many feet of mud and rock sixty miles downstream. Seven debris flows large enough to reach Puget Sound have occurred in the past 6,000 years.
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Related Content
How dangerous is Mount Rainier?
Although Mount Rainier has not produced a significant eruption in the past 500 years, it is potentially the most dangerous volcano in the Cascade Range because of its great height, frequent earthquakes , active hydrothermal system , and extensive glacier mantle. Mount Rainier has 25 major glaciers containing more than five times as much snow and ice as all the other Cascade volcanoes combined. If...
How would an eruption of Mount Rainier compare to the 1980 eruption of Mount St. Helens?
Eruptions of Mount Rainier usually produce much less volcanic ash than do eruptions at Mount St. Helens . However, owing to the volcano's great height and widespread cover of snow and glacier ice, eruption triggered debris flows ( lahars ) at Mount Rainier are likely to be much larger--and will travel a greater distance--than those at Mount St. Helens in 1980. Furthermore, areas at risk from...
How many eruptions have there been in the Cascades during the last 4,000 years?
Eruptions in the Cascades have occurred at an average rate of one to two per century during the last 4,000 years. Future eruptions are certain. Learn more: Eruptions in the Cascade Range During the Past 4,000 Years USGS Cascades Volcano Observatory
How much ash was there from the May 18, 1980 eruption of Mount St. Helens?
During the 9 hours of vigorous eruptive activity on May 18, 1980, about 540 million tons of ash from Mount St. Helens fell over an area of more than 22,000 square miles (57,000 square kilometers). The total volume of the ash before its compaction by rainfall was about 0.3 cubic mile (1.3 cubic kilometers), equivalent to an area the size of a football field piled about 150 miles (240 kilometers)...
How far did the ash from Mount St. Helens travel?
The May 18, 1980 eruptive column at Mount St. Helens fluctuated in height through the day, but the eruption subsided by late afternoon. By early May 19, the eruption had stopped. By that time, the ash cloud had spread to the central United States. Two days later, even though the ash cloud had become more diffuse, fine ash was detected by systems used to monitor air pollution in several cities of...
Title: The USGS Cascades Volcano Observatory - Research, monitoring, and the science of preparing society for low-probability, high-consequence events
Mount Rainier volcano looms over Puyallup Valley, near Orting, Washington.
Mount Rainier volcano looms over Puyallup Valley, near Orting, Washington.
Mount Rainier volcano looms over Puyallup Valley, near Orting, Washington.
Mount Rainier volcano looms over Puyallup Valley, near Orting, Washington.
The May 18, 1980 eruption of Mount St. Helens triggered a growth in volcano science and volcano monitoring. Five USGS volcano observatories have been established since the eruption. With new technologies and improved awareness of volcanic hazards USGS scientists are helping save lives and property across the planet.
The May 18, 1980 eruption of Mount St. Helens triggered a growth in volcano science and volcano monitoring. Five USGS volcano observatories have been established since the eruption. With new technologies and improved awareness of volcanic hazards USGS scientists are helping save lives and property across the planet.
House engulfed by debris flows generated in response to a rainstorm on February 6, 2010. This house was west of Briar Wood Canyon in southern California. The small, but steep and rugged drainage basin above this home was burned the previous summer by the Station Fire, the largest fire in the history of Los Angeles County.
House engulfed by debris flows generated in response to a rainstorm on February 6, 2010. This house was west of Briar Wood Canyon in southern California. The small, but steep and rugged drainage basin above this home was burned the previous summer by the Station Fire, the largest fire in the history of Los Angeles County.
House damaged by debris flows generated in Mullally Canyon in response to a rainstorm on February 6, 2010. The drainage basin above this home was burned the previous summer by the Station Fire, the largest fire in the history of Los Angeles County.
House damaged by debris flows generated in Mullally Canyon in response to a rainstorm on February 6, 2010. The drainage basin above this home was burned the previous summer by the Station Fire, the largest fire in the history of Los Angeles County.
Welcome to CoreFacts, where we're always short on time and big on science. I'm Steve Sobieszczyk. Let's get right to it, today's question is:
What is the greatest hazard presented by Mount Rainier?
Welcome to CoreFacts, where we're always short on time and big on science. I'm Steve Sobieszczyk. Let's get right to it, today's question is:
What is the greatest hazard presented by Mount Rainier?
Geologic field-trip guide to volcanism and its interaction with snow and ice at Mount Rainier, Washington
How would a volcanic eruption affect your Tribe?
When volcanoes fall down—Catastrophic collapse and debris avalanches
2018 update to the U.S. Geological Survey national volcanic threat assessment
When erupting, all volcanoes pose a degree of risk to people and infrastructure, however, the risks are not equivalent from one volcano to another because of differences in eruptive style and geographic location. Assessing the relative threats posed by U.S. volcanoes identifies which volcanoes warrant the greatest risk-mitigation efforts by the U.S. Geological Survey and its partners. This update
Lahar—River of volcanic mud and debris
U.S. Geological Survey Volcano Hazards Program—Assess, forecast, prepare, engage
Mount Rainier— Living safely with a volcano in your backyard
Eruptions in the Cascade Range during the past 4,000 years
Geologic hazards at volcanoes
Living with a volcano in your backyard: An educator's guide with emphasis on Mount Rainier
Debris-flow hazards caused by hydrologic events at Mount Rainier, Washington
Catastrophic debris flows transformed from landslides in volcanic terrains : mobility, hazard assessment and mitigation strategies
Related Content
- FAQ
How dangerous is Mount Rainier?
Although Mount Rainier has not produced a significant eruption in the past 500 years, it is potentially the most dangerous volcano in the Cascade Range because of its great height, frequent earthquakes , active hydrothermal system , and extensive glacier mantle. Mount Rainier has 25 major glaciers containing more than five times as much snow and ice as all the other Cascade volcanoes combined. If...
How would an eruption of Mount Rainier compare to the 1980 eruption of Mount St. Helens?
Eruptions of Mount Rainier usually produce much less volcanic ash than do eruptions at Mount St. Helens . However, owing to the volcano's great height and widespread cover of snow and glacier ice, eruption triggered debris flows ( lahars ) at Mount Rainier are likely to be much larger--and will travel a greater distance--than those at Mount St. Helens in 1980. Furthermore, areas at risk from...
How many eruptions have there been in the Cascades during the last 4,000 years?
Eruptions in the Cascades have occurred at an average rate of one to two per century during the last 4,000 years. Future eruptions are certain. Learn more: Eruptions in the Cascade Range During the Past 4,000 Years USGS Cascades Volcano Observatory
How much ash was there from the May 18, 1980 eruption of Mount St. Helens?
During the 9 hours of vigorous eruptive activity on May 18, 1980, about 540 million tons of ash from Mount St. Helens fell over an area of more than 22,000 square miles (57,000 square kilometers). The total volume of the ash before its compaction by rainfall was about 0.3 cubic mile (1.3 cubic kilometers), equivalent to an area the size of a football field piled about 150 miles (240 kilometers)...
How far did the ash from Mount St. Helens travel?
The May 18, 1980 eruptive column at Mount St. Helens fluctuated in height through the day, but the eruption subsided by late afternoon. By early May 19, the eruption had stopped. By that time, the ash cloud had spread to the central United States. Two days later, even though the ash cloud had become more diffuse, fine ash was detected by systems used to monitor air pollution in several cities of...
- Multimedia
PubTalk 2/2018 — USGS Cascades Volcano ObservatoryPubTalk 2/2018 — USGS Cascades Volcano ObservatoryPubTalk 2/2018 — USGS Cascades Volcano Observatory
Title: The USGS Cascades Volcano Observatory - Research, monitoring, and the science of preparing society for low-probability, high-consequence events
Title: The USGS Cascades Volcano Observatory - Research, monitoring, and the science of preparing society for low-probability, high-consequence events
Mount Rainier Looms over the Puyallup Valley, WashingtonMount Rainier Looms over the Puyallup Valley, WashingtonMount Rainier volcano looms over Puyallup Valley, near Orting, Washington.
Mount Rainier volcano looms over Puyallup Valley, near Orting, Washington.
Mount Rainier looms over the Puyallup Valley, WashingtonMount Rainier looms over the Puyallup Valley, WashingtonMount Rainier volcano looms over Puyallup Valley, near Orting, Washington.
Mount Rainier volcano looms over Puyallup Valley, near Orting, Washington.
Mount St. Helens: A Catalyst for ChangeThe May 18, 1980 eruption of Mount St. Helens triggered a growth in volcano science and volcano monitoring. Five USGS volcano observatories have been established since the eruption. With new technologies and improved awareness of volcanic hazards USGS scientists are helping save lives and property across the planet.
The May 18, 1980 eruption of Mount St. Helens triggered a growth in volcano science and volcano monitoring. Five USGS volcano observatories have been established since the eruption. With new technologies and improved awareness of volcanic hazards USGS scientists are helping save lives and property across the planet.
Debris Flow DamageHouse engulfed by debris flows generated in response to a rainstorm on February 6, 2010. This house was west of Briar Wood Canyon in southern California. The small, but steep and rugged drainage basin above this home was burned the previous summer by the Station Fire, the largest fire in the history of Los Angeles County.
House engulfed by debris flows generated in response to a rainstorm on February 6, 2010. This house was west of Briar Wood Canyon in southern California. The small, but steep and rugged drainage basin above this home was burned the previous summer by the Station Fire, the largest fire in the history of Los Angeles County.
Debris Flow Damage in CaliforniaHouse damaged by debris flows generated in Mullally Canyon in response to a rainstorm on February 6, 2010. The drainage basin above this home was burned the previous summer by the Station Fire, the largest fire in the history of Los Angeles County.
House damaged by debris flows generated in Mullally Canyon in response to a rainstorm on February 6, 2010. The drainage basin above this home was burned the previous summer by the Station Fire, the largest fire in the history of Los Angeles County.
What is the greatest hazard presented by Mount Rainier?What is the greatest hazard presented by Mount Rainier?Welcome to CoreFacts, where we're always short on time and big on science. I'm Steve Sobieszczyk. Let's get right to it, today's question is:
What is the greatest hazard presented by Mount Rainier?
Welcome to CoreFacts, where we're always short on time and big on science. I'm Steve Sobieszczyk. Let's get right to it, today's question is:
What is the greatest hazard presented by Mount Rainier?
Mount Rainier seen from Puyallup, Washington - Publications
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Geologic field-trip guide to volcanism and its interaction with snow and ice at Mount Rainier, Washington
Mount Rainier is the Pacific Northwest’s iconic volcano. At 4,393 meters and situated in the south-central Cascade Range of Washington State, it towers over cities of the Puget Lowland. As the highest summit in the Cascade Range, Mount Rainier hosts 26 glaciers and numerous permanent snow fields covering 87 square kilometers and having a snow and ice volume of about 3.8 cubic kilometers. It remainAuthorsJames W. Vallance, Thomas W. SissonHow would a volcanic eruption affect your Tribe?
Volcanic eruptions are rare, but when they occur, they can profoundly affect nearby communities. In order to determine which communities are at risk, and in order for those communities to mitigate their risk, communities need to know whether they are in or near volcano hazard zones and have basic information about the hazards within those zones. In addition, individuals need to know whether they lAuthorsCynthia A. Gardner, Joseph A. BardWhen volcanoes fall down—Catastrophic collapse and debris avalanches
Despite their seeming permanence, volcanoes are prone to catastrophic collapse that can affect vast areas in a matter of minutes. Large collapses begin as gigantic landslides that quickly transform to debris avalanches—chaotically tumbling masses of rock debris that can sweep downslope at extremely high velocities, inundating areas far beyond the volcano. Rapid burial by the debris avalanches themAuthorsLee Siebert, Mark E. Reid, James W. Vallance, Thomas C. Pierson2018 update to the U.S. Geological Survey national volcanic threat assessment
When erupting, all volcanoes pose a degree of risk to people and infrastructure, however, the risks are not equivalent from one volcano to another because of differences in eruptive style and geographic location. Assessing the relative threats posed by U.S. volcanoes identifies which volcanoes warrant the greatest risk-mitigation efforts by the U.S. Geological Survey and its partners. This update
AuthorsJohn W. Ewert, Angela K. Diefenbach, David W. RamseyByVolcano Hazards Program, Volcano Science Center, Agrigan, Ahyi Seamount, Alamagan, Anatahan, Asuncion, Belknap, Black Butte Crater Lava Field, Black Rock Desert Volcanic Field, Blue Lake Crater, Carrizozo Lava Flow, Cascade Range Weekly Update, Cinnamon Butte, Clear Lake Volcanic Field, Coso Volcanic Field, Crater Lake, Craters of the Moon Volcanic Field, Daikoku Seamount , Davis Lake Volcanic Field, Devils Garden Lava Field, Diamond Craters Volcanic Field, Dotsero Volcanic Center, East Diamante, Esmeralda Bank, Farallon de Pajaros, Fukujin Seamount , Glacier Peak, Guguan, Haleakalā, Hell's Half Acre Lava Field, Hualālai, Indian Heaven Volcanic Field, Jordan Craters Volcanic Field, Kama‘ehuakanaloa, Kasuga 2, Kīlauea, Lassen Volcanic Center, Long Valley Caldera, Mammoth Mountain, Markagunt Plateau Volcanic Field, Maug Islands, Mauna Kea, Mauna Loa, Medicine Lake, Mono Lake Volcanic Field, Mono-Inyo Craters, Mount Adams, Mount Bachelor, Mount Baker, Mount Hood, Mount Jefferson, Mount Rainier, Mount Shasta, Mount St. Helens, Newberry, Ofu-Olosega, Pagan, Red Hill-Quemado Volcanic Field, Ruby, Salton Buttes, San Francisco Volcanic Field, Sand Mountain Volcanic Field, Sarigan, Soda Lakes, South Sarigan Seamount, Supply Reef, Ta'u Island, Three Sisters, Tutuila Island, Ubehebe Craters, Uinkaret Volcanic Field, Valles Caldera, Wapi Lava Field, Weekly Update, West Crater Volcanic Field, Yellowstone, Zealandia Bank, Zuni-Bandera Volcanic FieldLahar—River of volcanic mud and debris
Lahar, an Indonesian word for volcanic mudflow, is a mixture of water, mud, and volcanic rock flowing swiftly along a channel draining a volcano. Lahars can form during or after eruptions, or even during periods of inactivity. They are among the greatest threats volcanoes pose to people and property. Lahars can occur with little to no warning, and may travel great distances at high speeds, destroyAuthorsJon J. Major, Thomas C. Pierson, James W. VallanceU.S. Geological Survey Volcano Hazards Program—Assess, forecast, prepare, engage
At least 170 volcanoes in 12 States and 2 territories have erupted in the past 12,000 years and have the potential to erupt again. Consequences of eruptions from U.S. volcanoes can extend far beyond the volcano’s immediate area. Many aspects of our daily life are vulnerable to volcano hazards, including air travel, regional power generation and transmission infrastructure, interstate transportatioAuthorsWendy K. Stovall, Aleeza M. Wilkins, Charlie Mandeville, Carolyn L. DriedgerMount Rainier— Living safely with a volcano in your backyard
Majestic Mount Rainier soars almost 3 miles (14,410 feet) above sea level and looms over the expanding suburbs of Seattle and Tacoma, Washington. Each year almost two million visitors come to Mount Rainier National Park to admire the volcano and its glaciers, alpine meadows, and forested ridges. However, the volcano's beauty is deceptive - U.S. Geological Survey (USGS) research shows that Mount RaAuthorsCarolyn L. Driedger, William E. ScottEruptions in the Cascade Range during the past 4,000 years
Volcanoes have been erupting in the Cascade Range for over 500,000 years. During the past 4,000 years eruptions have occurred at an average rate of about 2 per century. This chart shows 13 volcanoes on a map of Washington, Oregon, and northern California and time lines for each showing the ages of their eruptions.AuthorsBobbie Myers, Carolyn L. DriedgerGeologic hazards at volcanoes
Most volcano hazards are associated with eruptions. However, some hazards, such as lahars and debris avalanches, can occur even when a volcano is not erupting.AuthorsBobbie Myers, Carolyn L. DriedgerLiving with a volcano in your backyard: An educator's guide with emphasis on Mount Rainier
Today’s residents, as well as residents of centuries past, consider Mount Rainier “the spiritual and cultural icon of the Pacific Northwest.” As a backdrop for many of the State’s residents, Mount Rainier offers beauty, solace, inspiration, and challenge. The mountain sets the daily mood for thousands of people who gaze at and respect it. There is no mistaking this object of admiration when peopleAuthorsCarolyn L. Driedger, Anne Doherty, Cheryl Dixon, Lisa M. FaustDebris-flow hazards caused by hydrologic events at Mount Rainier, Washington
At 4393 m, ice-clad Mount Rainier has great potential for debris flows owing to its precipitous slopes and incised steep valleys, the large volume of water stored in its glaciers, and a mantle of loose debris on its slopes. In the past 10,000 years, more than sixty Holocene lahars have occurred at Mount Rainier (Scott et al., 1985), and, in addition more than thirty debris flows not related to volAuthorsJames W. Vallance, Michelle L. Cunico, Steve P. SchillingCatastrophic debris flows transformed from landslides in volcanic terrains : mobility, hazard assessment and mitigation strategies
Communities in lowlands near volcanoes are vulnerable to significant volcanic flow hazards in addition to those associated directly with eruptions. The largest such risk is from debris flows beginning as volcanic landslides, with the potential to travel over 100 kilometers. Stratovolcanic edifices commonly are hydrothermal aquifers composed of unstable, altered rock forming steep slopes at high alAuthorsKevin M. Scott, Jose Luis Macias, Jose Antonio Naranjo, Sergio Rodriguez, John P. McGeehin - News