<P> Lake Tahoe is the second deepest lake in the U.S., with a maximum depth of 1,645 feet (501 m), trailing Oregon's Crater Lake at 1,949 ft (594 m). Tahoe is the 16th deepest lake in the world, and the fifth 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 km). The lake is so large that its surface is noticeably convex due to the curvature of the earth . 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 . Visibility may vary somewhat with atmospheric refraction; 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 . </P> <P> Approximately two - thirds of the shoreline is in California . 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 . Although highways run within sight of the lake shore for much of Tahoe's perimeter, many important 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 km) includes the land area that drains to the lake and the Lake Tahoe drainage divide traverses the same general area as the Tahoe Rim Trail . </P> <P> Lake Tahoe is fed by 63 tributaries . These drain an area about the same size as the lake and produce half its water, with the balance entering as rain or snow falling directly on it . </P> <P> The Truckee River is the lake's only outlet, 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 vast surface . 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, with a spillway at the dam controlling overflow . 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). 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 . </P>

Where does the water from lake tahoe come from