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Lake Tahoe is the second deepest lake in the United States and the tenth deepest in the world, with a maximum depth measured at 1,645 ft (501 m), near Crystal Bay, average depth of 1,000 ft (305 m). Crater Lake in Oregon is the deepest lake (1,949 ft or 594 m) in the United States.
The water in Lake Tahoe could cover a flat area the size of California 14 in (36 cm) deep.
The lake is 99.1 percent pure and known for its remarkable clarity. At times, it can extend to 75 ft.
Lake Tahoe is about 22 mi (35 km) long and l2 mi (19 km) wide and has 72 mi (116 km) of shoreline and a surface area of 191 mi2 (495 km2). The floor of the Lake Tahoe Basin is at an elevation of about 4,580 ft (1,396 m), which is lower than the surface of the Carson Valley to the east! With an average surface elevation of 6,225 ft (1,897 m) above sea level, Lake Tahoe is the highest lake of its size in the United State.
The water temperature near the surface generally cools to 40 to 50°F (4.5 to 10°C) during February and March and warms to 65 to 70°F (18 to 21°C) during August and September. Below a depth of 600 to 700 ft (183 to 213 m), the water temperature remains a constant 39°F (4.0°C).
A UC Davis study found that from 1969 to 2002 the average water temperature increased 0.88 degrees Fahrenheit (0.5 degrees Celsius).
Source: Facts about Lake Tahoe at the USGS
Lake Tahoe never freezes due to the depth and constant movement of water from the bottom to the surface although some protected areas such as Emerald Bay have been covered with a layer of ice.
The lake is fed by 63 streams and two hot springs. The Truckee River at Tahoe City is the only outlet for the lake, which eventually feeds northeast into Pyramid Lake, never reaching an ocean.
The only fish truly native to this area is the Lahontan cuthroat trout, though mackinaw, rainbow trout and kokanee salmon also inhabit Tahoe. Non-natives were introduced as early as the mid-1800s to provide food for miners as the Lahontan fishery was drastically depleted.
Why is it so blue?
Tahoe called the "Lake of the Sky", with its brilliant shades of blues, however the blue color isn't because of the blue sky. When the sky was gray from fires in in the Sacramento valley in 2008 the lake was still very blue. Water absorbs all colors of light except blue. The further through water light travels the more other colors are absorbed. Because it is so clear, light is not reflected back until most other colors are absorbed.
Clarity:
One reason for the clarity is that 38 % of the precipitation falling into the Lake Tahoe Basin falls directly upon the Lake. Of the remaining precipitation a significant amount falls on granite and decomposed granite, so picks up little pollution (nutrients and particulate matter) and drains through the marshes and meadows, which are a good filtering system for water. Another contributing factor is exportation of all sewage from the Basin.
33% of the pollution comes from the Tahoe Keys at the South Shore.
UC Davis researchers at the Tahoe Environmental Research Center, measure the lake's clarity every seven to 10 days by lowering a white, dinner-plate-sized disk (called a Secchi disk) into the water at fixed locations and noting the depth at which the disk disappears from sight.
In 1968, when Secchi measurements began, the disk could be seen at an average depth of 102.4 feet. It is now about 72 feet.
Conservation and Development
See Tahoe Conservation
NW Tahoe - Truckee - Donner Development
Snowfall:
Average total snow fall at lake level is 14 ft. accumulating to a maximum depth of 2.8 ft.
Ski areas report average snowfall of 24-38 feet.
See Weather.
Population: 20,000 in 1960 to more than 65,000 in 2003
See Also:
Tree Species
Tahoe History and Geology.
Facts about Lake Tahoe at the U.S. Geological Survey
Historical Lake Levels at BoatTahoe.com
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