Mirror Lake (Wallowa)

Reachcode: 17060105000773 | Area: 28.0 acres | Shoreline: 1.1 mi | View on Interactive Map

(From Atlas of Oregon Lakes, Johnson et al. 1985)  Mirror Lake is located high in the Eagle Cap Wilderness of northeastern Oregon's Wallowa Mountains. At 26 acres in size it is the largest of the many lakes in an area known as the Lake Basin. Other nearby lakes include Horseshoe, Douglas and Moccasin Lakes; the latter receives the outflow from Mirror Lake. Minam Lake is located over a ridge to the west, and Glacier Lake over a ridge to the south. The imposing presence of Eagle Cap Mountain looms to the south of Mirror Lake and can be seen reflected in the water. The lake basin is the most popular destination for visitors to the Eagle Cap Wilderness, and is quite busy from July 4 through Labor Day. There are a large number of undeveloped, but heavily used campsites around the lake. Eastern brook trout are the only fish in Mirror Lake and produce well in late summer.

The lake consists of a single deep basin (maximum depth = 75 feet) carved out by an alpine glacier. Because of the high altitude (7560 feet), the water remains cool throughout the year. Bottom water remains perennially at the temperature of maximum density (39 degrees Fahrenheit; 4 degrees Celsius), and even at the height of summer stratification, surface temperatures seldom reach 59 degrees Fahrenheit (15 degrees Celsius). Water in the lake contains very little dissolved ionic material, and conductivity and alkalinity are among the lowest for lakes in the state. There is a modest amount of dissolved calcium, resulting from the weathering of glacial flour in the drainage basin. Water transparency is exceptionally high (41.7 feet; 12.7 meters) and is exceeded by only a few lakes in Oregon. The concentration of phosphorus is moderate, but phytoplankton populations and chlorophyl concentrations are very low. The productivity is sufficient to support the small population of resident brook trout. In summary, Mirror Lake is an exceptionally pristine alpine lake, and is classified as oligotrophic.