Age of Lake Tahoe: 2 million years
Fed By: 63 streams and 2 hot springs
Only Outlet: Truckee River (Tahoe City)
Watershed Area: 312 square miles (808 sq km)
Average Water Temperature: 42.1˚F (5.61˚C)
Average Surface Water Temperature: 51.9˚F (11.1˚C)
Average Surface Temperature in July: 64.9˚F (18.3˚C)
Highest Peak: Freel Peak at 10,881 feet (3,317 m)
Average Snowfall: 409 inches (10.4 m)
Permanent Population: 70,000
Number of Visitors: 15 million annually
Lake Tahoe is located in the states of California and Nevada, with two-thirds in California.
2021: 61 feet avg. depth (18.6 m)
1968: First recorded at 102.4 feet (31.21 m)
Average depth: 1,000 feet (304 m)
Maximum depth: 1,645 feet (501 m)
Lake Tahoe is the second deepest lake in the U.S. (Crater Lake in Oregon, at 1,932 feet, or 589 m, is the deepest), and the 11th deepest in the world.
Volume: 39 trillion gallons (147.6 trillion liters)
There is enough water in Lake Tahoe to supply everyone in the United States with more than 75 gallons (284 liters)
of water per day for 5 years.
Natural rim: 6,223’ (1,897 m)
Lake Tahoe sits at an average elevation of between 6,223’ and 6,229.1’. (1,897-1,899 m) The top 6.1’ (1.8 m) of water is controlled by the dam in Tahoe City and holds up to 744,600 acre feet of water (91,845 m).
Size: 22 miles long, 12 miles wide (35 km long, 19 km wide)
Lake Tahoe is as long as the English Channel is wide.
Shoreline: 72 miles (116 km)
Lake Tahoe has a surface area of 191 square miles (307 km). If Lake Tahoe were emptied, it would submerge California under 15 inches of water (.38 m).
Why is the lake blue?
The Lake of the Sky appears blue in color as other colors in the light spectrum are absorbed and the blue light is scattered back.
How The Lake Was Formed
About 3 to 5 million years ago, the valley that would become the Tahoe Basin sank between parallel fractures in the Earth’s crust as the mountains on either side continued to rise. A shallow lake began to form in the resulting valley.
Roughly 2 to 3 million years ago, erupting volcanoes blocked the outlet, forcing the lake to rise hundreds of feet above its current elevation, and eventually eroded down to near its current outlet.
Between 1 million and 20,000 years ago, large masses of glacial ice covered the west side of the Tahoe Basin. Current geologic theory suggests an earthen berm (moraine) left by a receding glacier near Olympic Valley acted as a dam, causing the lake level to rise and then draw down rapidly when the dam catastrophically failed. Between 7,000 and 15,000 years ago, a 4-mile segment of the West Shore collapsed into the Lake causing a massive submerged debris avalanche, widening the Lake by three miles and creating McKinney Bay.1
The Tahoe Basin is mostly granite, with little topsoil, and therefore few nutrients have washed into the lake to promote the growth of algae and other organisms that make water murky.
As well, 40 percent of the precipitation falling into the Tahoe Basin lands directly on the lake. The remaining precipitation drains through the decomposed granite soil found in marshes and meadows, creating a good filtering system for water.
Urbanization of the Tahoe Basin has eliminated 75 percent of its marshes, 50 percent of its meadows and 35 percent of its steam zone habitats. About 85 percent of all wildlife in the Tahoe Basin use these habitats.
About the lake
Lake Tahoe is located in the states of California and Nevada, with two-thirds in California. It is fed by 63 streams and two hot springs.
The Truckee River is Tahoe’s only outlet and flows from the dam in Tahoe City east through Reno and eventually drains into Pyramid Lake in the Nevada desert.
However, water releases are not permitted when the lake surface level falls below the natural rim at 6,223’ (1,897 m). The lowest lake level on record (measured since 1900) was 6,220.26’ (1,896 m) on Nov. 30, 1992.
The Lake of the Sky appears blue in color as other colors in the light spectrum are absorbed and blue light is scattered back.
The University of California, Davis, operates the Tahoe Environmental Research Center, which monitors, among other things, the clarity of Lake Tahoe. Clarity has been measured since 1968 and was first recorded at 102.4’.
The waters of Lake Tahoe were clear to an average depth of 61’ (18.6m) in 2021. Lake Tahoe is losing clarity because of algae growth fueled by nitrogen and phosphorus.
Lake Tahoe’s discovery
The first recorded discovery of Lake Tahoe by white explorers was on Feb. 14, 1844, when John Charles Frémont and Charles Preuss spotted the lake from atop Red Lake Peak. The lake went through several names before it was officially named Tahoe in 1945.
Tahoe is a mispronunciation of the first two syllables of the Washo’s word for the lake – Da ow a ga, which means “edge of the lake.”
Learn more: Visit the Tahoe Science Center in Incline Village or tahoesciencecenter.org.
Sources: Tahoe Environmental Research Center, U.S. Geological Survey, U.S. Forest Service, “Tahoe Place Names” and David Antonucci (denoted by 1).