TT #16 ~ Cascade Mountain Range Volcanoes

I have driven the I-5 from Washington to California so many times and have been fascinated by the interesting peaks along the way. It’s amazing to think that these peaks are all volcanoes. Up Front I want to say I only took two of the photos that are posted here. I’m getting credit for some of these wonderful shots but I did not take them. Cheers!

1. Lassen Peak is one of the youngest of the Cascade volcanoes. Lassen Peak last erupted in 1914-1917! The only other volcano in the continental United States to have erupted in the 20th century is Mount St. Helens in Washington.

2. Mt. Shasta: The two main peaks formed within the last 10,000 years. Over the last 4,500 years, Mount Shasta has erupted on average every 600 years. It last erupted around 1786 A.D.
Mount Shasta is also one of the most prominent topographic features on the planet, rising 11,000 feet (3,350 meters) above the plain below.

3. Crater Lake began about 500,000 years ago as Mount Mazama, a progressively building volcanic cone. About 7,700 years ago, cataclysmic eruptions, 42 times greater than those of Mount St. Helens in 1980, spewed ash over 5,000 square miles. The eruptions covered parts of 8 U.S. states and 3 Canadian provinces with 6 inches of ash. Some local areas were buried in over 50 feet of ash. After the volcano’s magma chamber had emptied, the top of the mountain collapsed, resulting in a caldera. Up until about 4,000 years ago, volcanic activity within the caldera prevented the formation of a lake and built the cinder cones Wizard Island and the submerged Merriam Cone. Over the last 4,000 years, the volcano has been quiet, and the lake began to fill the caldera. Crater Lake is now the deepest lake in the United States with a maximum depth of 1,932 feet (589 meters) and an average depth of 1,500 feet (457 meters).

4. Mount McLoughlin Volcano  McLoughlin is easily recognized from as far away as Medicine Lake in California, along I-5 between Yreka, California, and Medford, Oregon, or around the rim of Crater Lake. Although it is the tallest volcano between Shasta and Crater Lake, McLoughlin, with a volume of only 13 cubic kilometers, is dwarfed by the bulk of Shasta (350 cubic kilometers) and Mazama (130 cubic kilometers [Crater Lake]). – Smith, 1990, IN: Wood and Kienle

5. Mount Thielsen:  Extinct. The summit has been eroded into sharp peaks by glaciation.

6.The Three Sisters: From left to right, the three peaks are called the South Sister, the Middle Sister, and the North Sister. Middle and North Sisters are extinct; South Sister is dormant.

7. The peak of Mount Jefferson rises above the Mount Jefferson Wilderness.
Volcano Status: Extinct. The last eruption occurred over 50,000 years ago.

8. Mount Hood at Mirror Lake is Dormant.  Last erupted in 1865 A.D.
Peak Elevation: 11,245 feet (3,426 meters).

9. Mount Adams from inside Mount St. Helens Volcano Status: Dormant.
Age/Last Eruption: The last eruption occurred over 3,500 years ago.
Peak Elevation: 12,276 feet (3,742 meters).

10. Mount St. Helens.  Status: Active. Fumaroles within the present crater and a building resurgent dome.
Age/Last Eruption: One of the youngest of the Cascade volcanoes, forming about 40,000 years ago. Major eruption on May 18, 1980.
Peak Elevation: Presently 8,363 feet (2,549 meters); prior to the 1980 eruption: 9,679 feet (2,950 meters).  The first photo below of Mt. St. Helens I took from the plane on a recent flight. The second photo is of the acutal eruption taken in 1980.

11. Mount Rainier is just southeast of the Seattle/Tacoma metropolitan area, making it one of the most dangerous volcanoes in the world. Its enormous, glacier-capped top is the source of numerous debris avalanches, some of which have flowed all the way to the Puget Sound.
Volcano Status: Dormant.
Last Eruption: The last eruption occurred about 2,200 years ago. The last major debris avalanche occurred in 1882.

12. Glacier Peak is the most remote of the five dormant/active volcanoes in Washington. It has produced some of the largest and most explosive eruptions in the state. There are at least 12 glaciers on the sides of the volcano. Most of the loose pyroclastic deposits have been eroded by these glaciers.
Volcano Status: Dormant.

13. Mount Baker is the northernmost of the Cascade volcanoes in the United States.
Volcano Status: Dormant. Active fumaroles from 1975 to the present.
Age/Last Eruption: Eruptions began over one million years ago. One of the most recent eruptions formed Sherman Crater in 1843. The last major debris avalanche (lahar) occurred in 1891. Some steam activity was noted as recently as 1975-1978. 

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