The Cascade Mountains are a generally north-to-south range of mountains near the western seaboard of the United States and Canada that runs for a length of 725 miles (1,167 kilometers) with 92% occurring within the confines of the US. It also has an east-to-west extent of about 194 miles (312 kilometers), and the highest peak for the Cascade Mountains is Mount Rainier, at 14,411 feet (4,392 meters). The Cascade Range is known for its rugged terrain, snow-capped peaks, and string of volcanoes. Some of the volcanoes are still active, the most famous being Mt. St. Helens in southwest Washington state, which had a major eruption on 18 May 1980.
While Mount Rainier is the tallest mountain in the Cascades and also an active volcano, several others are close to it in height, including Mount Shasta in northern California at 14,162 feet (4,317 meters) and Mount Adams directly east of Mt. St. Helens, at 12,276 feet (3,742 meters). Mount Rainier, however, carries the distinction of having a US National Park named after it. Mount Rainier National Park is a popular site for experienced mountain climbers and hikers interested in the old growth forests, meadows, and wildflowers of the glacier-fed region of the North Cascades. The Paradise Jackson Visitor Center at the park recorded a record snowfall in the 1971 to 1972 season of 93.5 feet (28.50 meters).
The Cascade Mountains compose a small part of the Pacific Ring of Fire, which is a Pacific ocean string of volcanoes that covers 154,441 square miles (400,000 square kilometers). It contains about 75% of the world's active volcanoes. Of all the mountain ranges in North America, the Cascade Mountains has the majority of active volcanoes, with 18 of them that have erupted within the past 2,000 years and 7 of them that have erupted in the past 200 years.
The famous Lewis and Clark expedition that explored the Pacific coast region of the western US between 1804 to 1806 was responsible for identifying five of the active volcanoes in the Cascade Mountains range. These include Mount Rainier, Adams, and St. Helens to the north of the Columbia river basin in what is now Washington state, and Mount Hood and Jefferson south of there in the state of Oregon. The Columbia river itself is considered unique, as it splits the Cascade Mountains into a northern and southern range as it flows from the Pacific ocean west to east between Mount Adams north of it and Mount Hood to its south. The river basin created by the Columbia is considered the only major water and air flow region between the Pacific ocean, Cascade Mountains, and interior US along the western border, making the river one of the most turbulent and windy rivers to navigate in the world.