Mount Hood Volcano
Mt Hood 75 km ESE of Portland is Oregon's highest peak and one of the most prominent of the Cascades volcanoes. It is probably the only volcano in Oregon which has erupted in historic times (last confirmed activity in 1865-66).
Andesite-dacite lava domes form the glacially eroded summit complex.
The main hazard from Mt Hood are posed by pyroclastic flows and mud flows (lahars) in case of an eruption. These would travel downstream river beds radiating from the volcano and threaten communities in this area.
Flank failure and debris avalanche risk:
Scientist also warn that due to heavy alteration of rocks by fumarolic and hydrothermal activity large parts of the upper volcanic edifice are structurally unstable and could be prone to massive slope failure. This would trigger catastrophic debris flows, such as has happened at Mt St. Helens in 1980 and have happened in Mt Hood's geologic past as well. More than 100,000 years ago, a large collapse produced a debris avalanche and lahar that traveled north down the Hood River valley and crossed the Columbia River, and a smaller, but still sizeable event like this repeated itselfa about 1500 years ago.
Mount Hood volcano eruptions: 1907(?), 1869(?), 1865-66, 1859, 1854(?), 1853(?), 1795 ± 5 yr, 1765 ± 5, 390 ± 150, 510 AD ± 150, 300 AD ± 200, 4940 BC ± 150
Latest nearby earthquakes
| Date and Time | Mag / Depth | Distance / Location | |||
|---|---|---|---|---|---|
| Apr 30, 05:14 pm (Universal Time) | 0.5 6.3 km | 11 km (7 mi) to the W | 7 km WNW of Government Camp, Oregon | Info | |
| Apr 30, 04:43 pm (Universal Time) | 0.2 7 km | 11 km (6.9 mi) to the W | 7 km NW of Government Camp, Oregon | Info | |
| Apr 30, 02:13 am (Universal Time) | 0.1 4.9 km | 4.5 km (2.8 mi) to the W | Clackamas County, 34 mi east of Gresham, Multnomah County, Oregon, United States | Info | |
| Monday, April 21, 2025 GMT (1 quake) | |||||
| Apr 21, 06:51 pm (Universal Time) | 0.2 0.2 km | 0.6 km (0.4 mi) to the E | 9 km NE of Government Camp, Oregon | Info | |
| Sunday, April 20, 2025 GMT (1 quake) | |||||
| Apr 20, 06:48 am (GMT -7) | 0.7 2.1 km | 1.4 km (0.8 mi) to the SW | Clackamas County, 30 mi southwest of The Dalles, Wasco County, Oregon, United States | Info | |
Background
Mt Hood volcano has had at least 4 major eruptive periods during the past 15,000 years. The last three occurred within the past 1800 years from vents high on the SW flank and produced deposits that were distributed primarily to the south and west along the Sandy and Zigzag rivers. The last eruptive period took place around 170-220 years ago, when growth of the Crater Rock lava dome was accompanied by pyroclastic flows and lahars down the White and Sandy rivers. The Sandy River lahar deposits extended to the west as far as the Columbia River and were observed by members of the 1804-1805 Lewis and Clark expedition within a few years of their emplacement. Minor 19th-century eruptions were witnessed from Portland.About 1,500 years ago, a moderate-size debris avalanche originating on the upper southwest flank of Mount Hood (see photograph) produced a lahar
that flowed down the Zigzag and Sandy River valleys. It swept over the entire valley floor in the Zigzag-Wemme-Wildwood area, and inundated a broad area near Troutdale, where the Sandy flows into the Columbia River—a total distance of about 90 kilometers (55 miles). More than 100,000 years ago, a much larger debris avalanche and related lahar flowed down the Hood River, crossed the Columbia River, and flowed several kilometers up the White Salmon River on the Washington side. Its deposit must have dammed the Columbia River at least temporarily.
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Sources:
GVP Mt Hood information
VOLCANO HAZARDS IN THE MOUNT HOOD REGION, OREGON USGS Open File Report 97-89
Mount Hood Volcano Photos
8 October, 2009 (Photo: volcanomike)
Significant volcanic eruptions: Mount Hood volcano
Additionally, there are 4 uncertain or discredited eruptions from Mount Hood volcano.
| Date | Note | VEI | Deaths | Damage | ||
|---|---|---|---|---|---|---|
| 1980 Dec 25 (eruptive episode | Historical obs./docs. | 0 | 1 | Info | ||
| 1934 (eruptive episode | Historical obs./docs. | 0 | 1 | Info | ||
Discredited Eruption | ||||||
?? | Uncertain Eruption | ? | ||||
Historical obs./docs. | 2 | |||||
Historical obs./docs. | 2 | |||||
?? | Uncertain Eruption | ? | ||||
?? | Uncertain Eruption | ? | ||||
| Crater Rock | ? | |||||
| Crater Rock | ? | |||||
| Lower NE flank (SSW of Parkdale) | 2 | |||||
Mount Hood Volcano FAQ
+When was the last eruption of Mount Hood volcano?
The last confirmed eruption of Mount Hood occurred during 1865 - 1866.
+How often does Mount Hood volcano erupt?
Since 1859, Mount Hood volcano has had at least 2 historically documented eruptions. This means that it erupts on average every 83 years.
Many eruptions of Mount Hood have lasted more than one year. In total, the volcano has been in eruption during 3 out of 166 years until now. In other words, Mount Hood has been active at least one in 55.3 years on average. Note that this value is likely an underestimate, because the known history of eruptions from Mount Hood is likely incomplete, especially further back in time.
+When was the largest eruption of Mount Hood volcano?
The largest eruption of Mount Hood volcano in historic times occurred during 1865 - 1866. It ranks as a strombolian to vulcanian eruption with a magnitude 2 on the VEI (Volcanic Explosivity Index) scale.
Latest satellite images
Mount Hood Volcano Maps
