Mt. Rainier, at 14,411 feet, is the highest mountain in Washington, and third highest in the lower 48 states. With 26 glaciers covering 36 square miles, it now has more glaciers than Glacier National Park. Five rivers flow from these glaciers as they melt. Mt. Rainier is one of several mountains in the Cascade Range classified as an active volcano, probably the most dangerous of all. An eruption could potentially destroy numerous towns and kill up to 150,000 people living around its base. Instantly melting ice would form massive lahars (flows of mud and debris) speeding down the mountain and traveling as much as 50-60 miles.
The last significant eruption of Mt. Rainier took place in the early 19th century, but smaller eruptions were reported periodically through the second half of the century. Because an eruption is thought to be "overdue", monitoring devices have been placed all over the mountain. However, it is questionable whether a warning would allow enough time for much of the endangered population to evacuate.
Prior to an eruption, however, Mt. Rainier is one of the most beautiful places in the U.S. and provides enormous recreational opportunity. It became our 5th national park in 1899. Some 8000 to 13,000 people attempt to climb it each year, over numerous routes, and roughly half of them succeed. A small number die in the attempt. Hiking is a very popular activity, and many people visit to enjoy the magnificent wildflowers that bloom during summer months. Of course, the mountain also has many lakes and streams, plus quite a few spectacular waterfalls.