Crater Lake National Park is characterized by cool summers (temperatures range from highs in the 60s to freezing) and moist winters. Crater Lake is one of the snowiest areas in the Northwest.
The 12,000-foot Mount Mazama collapsed 7,700 years ago after a violent eruption. This formed a caldera (a volcanic basin), which has filled with rainfall and snowmelt for thousands of years since. The result is Crater Lake, a place of immense beauty and extreme water clarity.
Dangerously sheer cliffs surround the deep, blue Crater Lake. Within the lake are two islands---Wizard Island and Phantom Ship. A mountain hemlock log, known as "The Old Man of Crater Lake," has been floating upright in the lake for more than 100 years.
Soil samples taken by the Natural Resources Conservation Service show that volcanic material from the eruption of Mount Mazama covers about 90 percent of the surface of the park. The remaining 10 percent, found along the western and southwestern edges of the park, formed on glacial ground moraines about 15,000 to 25,000 years ago.
A wealth of ferns, flowering herbs, wildflowers and lichens can be found within Crater Lake National Park. Tree species such as pines, firs, hemlock, spruce and cedar are abundant, as well as numerous varieties of shrubs and undergrowth.