Mount Rainier is a massive stratovolcano located 54 miles (87 km) southeast of Seattle in the state of Washington, United States. It is the most topographically prominent mountain in the contiguous United States and the Cascade Volcanic Arc, with a summit elevation of 14,411 ft (4,392 m). Mt. Rainier is considered one of the most dangerous volcanoes in the world, and it is on the Decade Volcano list. Because of its large amount of glacial ice, Mt. Rainier could potentially produce massive lahars that would threaten the whole Puyallup River valley.
Mount Rainier is the highest mountain in Washington and the Cascade Range. Mount Rainier has a topographic prominence of 13,211 ft (4,027 m), greater than K2, the world's second-tallest mountain, at 13,189 ft (4,020 m). On clear days it dominates the southeastern horizon in most of the Seattle-Tacoma metropolitan area to such an extent that locals sometimes refer to it simply as "the On days of exceptional clarity, it can also be seen from as far away as Portland, Oregon and Victoria, British Columbia.