Lake Tahoe

Lake Tahoe
Dáʔaw (Washo)
The south shore of Lake Tahoe in California, as seen from the west shore
Lake Tahoe Location of Lake Tahoe in California Show map of California Lake Tahoe Location of Lake Tahoe in Nevada Show map of Nevada Lake Tahoe Location of Lake Tahoe in the USA Show map of the United States
Lake Tahoe from space
Location	The Sierra Nevada of the U.S., along the state line of California and Nevada
Coordinates	39°N 120°W / 39°N 120°W / 39; -120
Lake type	Ancient lake, Geologic block faulting
Primary outflows	Truckee River
Basin countries	United States
Max. length	22 mi (35 km)
Max. width	12 mi (19 km)
Surface area	191 sq mi (490 km2):[1] Placer County (41%) El Dorado County (29%) Douglas County (13%) Washoe County (11%) Carson City (6%)
Average depth	1,000 ft (300 m)[1]
Max. depth	1,645 ft (501 m)
Water volume	36 cu mi (150 km3; 120,000,000 acre⋅ft)[2]
Residence time	650 years
Shore length1	71 mi (114 km)
Surface elevation	6,225 ft (1,897 m)[1]
Frozen	Rarely, in Emerald Bay[3]
Islands	Fannette Island
Settlements	Incline Village, NV South Lake Tahoe, CA Stateline, NV Tahoe City, CA Kings Beach, CA
1 Shore length is not a well-defined measure.

Lake Tahoe (/ˈtɑːhoʊ/; Washo: Dáʔaw) is a freshwater lake in the Sierra Nevada of the Western United States, straddling the border between California and Nevada. Lying at 6,225 ft (1,897 m) above sea level, Lake Tahoe is the largest alpine lake in North America,^[4] and at 122,160,280 acre⋅ft (150.7 km³) it trails only the five Great Lakes as the largest by volume in the United States. Its depth is 1,645 ft (501 m), making it the second deepest in the United States after Crater Lake in Oregon (1,949 ft or 594 m).^[1]

The lake was formed about two million years ago as part of the Lake Tahoe Basin, and its modern extent was shaped during the ice ages. It is known for the clarity of its water and the panorama of surrounding mountains on all sides.^[5] The area surrounding the lake is also referred to as Lake Tahoe, or simply Tahoe; its English name is derived from its Washo name, Dáʔaw.^[6] More than 75% of the lake's watershed is national forest land, covered by the Lake Tahoe Basin Management Unit of the United States Forest Service.

Lake Tahoe is a major tourist attraction in both Nevada and California. It is home to winter sports, summer outdoor recreation, and scenery enjoyed throughout the year. Snow and ski resorts are a significant part of the area's economy and reputation.^[7][8] The Nevada side also offers several lakeside casino resorts, with highways providing year-round access to the entire area.

The name for Lake Tahoe derives from the Washo word for the lake, Dáʔaw, meaning 'the lake.'^[9] Even though dáʔaw is used in the names of other lakes with modifiers (for example, Á’waku dáʔaw for Pyramid Lake, meaning 'trout lake'), it often is used without a modifier to refer to Lake Tahoe. This may be because of Tahoe's importance to Washo culture.^[10]

Lake Tahoe is the second deepest lake in the U.S., with a maximum depth of 1,645 feet (501 m),^[1][11] trailing Oregon's Crater Lake at 1,949 ft (594 m).^[11] Tahoe is the 17th^[12] deepest lake in the world, and the sixth deepest in average depth. It is about 22 mi (35 km) long and 12 mi (19 km) wide and has 72 mi (116 km) of shoreline and a surface area of 191 square miles (490 km²). The lake is so large that its surface is noticeably convex due to the curvature of the Earth.^[13] At lake level the opposing shorelines are below the horizon at its widest parts; by nearly 100 feet (30 m) at its maximum width, and by some 320 feet (98 m) along its length.^[14][15] Visibility may vary somewhat with atmospheric refraction;^[16] when the air temperature is much greater than the lake temperature, looming may occur where the lake surface or opposing shoreline is lifted above the horizon. Fata Morgana may be responsible for Tahoe Tessie sightings.

Approximately two-thirds of the shoreline is in California.^[17] The south shore is dominated by the lake's largest city, South Lake Tahoe, California, which adjoins the town of Stateline, Nevada, while Tahoe City, California, is located on the lake's northwest shore. Kings Beach, California, and Incline Village, Nevada anchor the lake's north shore.^{[clarification needed]} Although highways run within sight of the lake shore for much of Tahoe's perimeter, many important^{[clarification needed]} parts of the shoreline lie within state parks or are protected by the United States Forest Service. The Lake Tahoe Watershed (USGS Huc 18100200) of 505 sq mi (1,310 km²) is the land area that drains to the lake and the Lake Tahoe drainage divide traverses the same general area as the Tahoe Rim Trail.

Lake Tahoe is fed by 63 tributaries. These drain an area about the same size as the lake and produce half its water, the other half by direct precipitation.

The Truckee River is the lake's only outlet,^[4] flowing northeast through Reno, Nevada, into Pyramid Lake which has no outlet. It accounts for one third of the water that leaves the lake, the rest evaporating from the lake's surface. Evaporation is thought to account for 40 to 60 percent of the water usage.^[18] The flow of the Truckee River and the height of the lake are controlled by the Lake Tahoe Dam at the outlet. The natural rim is at 6,223 ft (1,897 m) above sea level. The maximum legal limit to which the lake can be allowed to rise in order to store water is at 6,229.1 ft (1,898.6 m); a spillway at the dam controls overflow.^[19] Around New Year 1996/1997 a Pineapple Express atmospheric river melted snow and caused the lake and river to overflow, inundating Reno and surrounding areas.^[20]

The Lake Tahoe Basin was formed by vertical motion (normal) faulting. Uplifted blocks created the Carson Range on the east and the main Sierra Nevada crest on the west. Down-dropping and block tilting (half-grabens) created the Lake Tahoe Basin in between.^[1] This kind of faulting is characteristic of the geology of the adjoining Great Basin to the east.

Lake Tahoe is the youngest of several extensional basins of the Walker Lane deformation zone that accommodates nearly 0.47 in (12 mm) per year of dextral shear between the Sierra Nevada-Great Valley Block and North America.^[21][22]

Three principal faults form the Lake Tahoe basin: the West Tahoe Fault, aligned between Meyers and Tahoe City, and which is the local segment of the Sierra Nevada Fault, extending on shore north and south of these localities;^[23] the Stateline/North Tahoe Fault, starting in the middle of the lake and creating the relief that forms Stateline, NV; and the Incline Village Fault, which runs parallel to the Stateline/North Tahoe Fault offshore and into Incline Village.^[24] The West Tahoe Fault appears to be the most active and potentially hazardous fault in the basin. A study in Fallen Leaf Lake, just south of Lake Tahoe, used seafloor mapping techniques to image evidence for paleoearthquakes on the West Tahoe and revealed the last earthquake occurred between 4,100 and 4,500 years ago.^[25] Subsequent studies revealed submarine landslides in Fallen Leaf Lake and Lake Tahoe that are thought to have been triggered by earthquakes on the West Tahoe fault and the timing of these events suggests a recurrence interval of 3,000–4,000 years.^[26]

Some of the highest peaks of the Lake Tahoe Basin that formed during the process of Lake Tahoe creation are Freel Peak at 10,891 feet (3,320 m), Monument Peak at 10,067 feet (3,068 m), Pyramid Peak at 9,984 feet (3,043 m) (in the Desolation Wilderness), and Mount Tallac at 9,735 feet (2,967 m).^[1] The north shore boasts three peaks at over 10,000 feet (3,048 m): Mount Rose at 10,785 feet (3,287 m), Mount Houghton at 10,490 feet (3,197 m) and Relay Peak at 10,388 feet (3,166 m). Mt. Rose is a very popular hiking and backcountry skiing destination.

Eruptions from the now-extinct volcano Mount Pluto formed a volcanic dam on the north side. Melting snow filled the southern and lowest part of the basin to form the ancestral Lake Tahoe. Rain and runoff added additional water.^[27]

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