Mount Hood

Mount Hood is an active stratovolcano located in the Cascade Range. It sits in the Pacific Northwest region of the United States. The mountain is positioned east-east-southeast of Portland, Oregon. It lies on the border between Clackamas and Hood River counties.

Much of the mountain is part of the Mount Hood National Forest. Large areas outside the ski resorts belong to the Mount Hood Wilderness. This peak is the highest mountain in the state of Oregon. It is also the fourth highest peak in the Cascade Range.

The volcano was created by a subduction zone near the Pacific Coast. In a subduction zone, parts of the Earth's crust move under one another. This process forms the Cascade Volcanic Arc. The summit area is glacially eroded. It contains several andesitic or dacitic lava domes. Andesite and dacite are specific types of volcanic rock. During the Pleistocene epoch, collapses caused avalanches and lahars. A lahar is a rapidly moving mudflow. These mudflows once traveled across the Columbia River to the north.

Mount Hood has experienced at least four major eruptive periods over 15,000 years. The last three eruptions happened within the past 1,800 years. These eruptions occurred from vents on the southwest flank. They produced deposits along the Sandy and Zigzag rivers. The volcano has reached a Volcanic Explosivity Index (VEI) of 2 at least three times. The most recent eruptive period ended roughly 170 to 220 years ago. During that time, dacitic lava domes and pyroclastic flows were produced. Crater Rock is a prominent feature below the summit. Scientists believe it is the remains of an eroded lava dome.

History and naming of the mountain involve many different perspectives. European explorers first named the peak on October 29, 1792. Lieutenant William Broughton named it after Samuel Hood, a British admiral.

Lewis and Clark also saw the mountain in 1805. They called it "Falls Mountain" or "Timm Mountain." Indigenous names for the mountain are difficult to establish with certainty. Some legends associate the name Wy'east with the peak. One story says the mountain was created by the Great Spirit, Sahale. In this version, Wy'east was a brave who became the mountain. Other stories involve battles between tribal chiefs that created volcanoes.

The mountain is a major site for recreation and tourism. It attracts about 10,000 climbers every year. There are four main ski areas on the mountain. These are Timberline Lodge, Mount Hood Meadows, Skibowl, and Cooper Spur. Timberline Lodge is a National Historic Landmark. It offers the only year-round lift-served skiing in North America.

The mountain also contains 12 named glaciers and snowfields. These include the Eliot Glacier. Visitors can use several remaining shelters like the Tilly Jane A-frame cabin. The forest includes more than 250 miles of hiking trails.

Scientists monitor the volcano to ensure public safety. The U.S. Geological Survey (USGS) calls it "potentially active." The estimated chance of an eruption in the next 30 years is 3% to 7%.

The USGS Cascades Volcano Observatory tracks seismic activity. They monitor earthquake swarms and gas emissions. Vents near the summit emit carbon dioxide and sulfur dioxide. Recent evidence of activity includes fumaroles and hot springs. Fumaroles are openings that release volcanic gases. In 2020, three new monitoring stations were installed. These include seismometers to measure earthquakes and GPS instruments to track ground movement.

There is an ongoing debate regarding how to monitor the mountain. A conflict exists between protecting the environment and ensuring safety. In 2014, a scientist proposed installing new instruments. This project was opposed by the conservation group Wilderness Watch. This was because the locations were in a protected wilderness area. Despite this, the stations were eventually installed in 2020. These tools help experts watch for changes in the volcano. Monitoring helps manage the risks posed by potential lahars. Glaciers on the upper slopes can become dangerous during an eruption.