About Tahoe

Tahoe’s clean air and water are the keys to the Lake’s dazzling blue color. The surface of Lake Tahoe is blue in part because it’s reflecting the sky, but there is more to this phenomenon. Water as crystal clear as Tahoe’s absorbs red light, leaving the rich blue color that we all see.

Tahoe is so clear that in some places objects can be seen to depths of over 70 feet. One reason is that 40 percent of the precipitation falling into the Lake Tahoe Basin falls directly upon the Lake. Much of the remaining precipitation drains through marshes and meadows, which are an effective filtration system that remove fine particles before water enters the Lake. Unfortunately, many of the Lake’s natural filters have been disturbed by unchecked development from the 20th century. As a result, Tahoe’s clarity has diminished considerably since 1968 when clarity was measured at over 100 feet.

The water contained in Lake Tahoe is enough to cover a flat area the size of California to a depth of 14 inches.

Lake Tahoe is 22 miles long, 12 miles wide, and has 72 miles of shoreline. The surface area covers 191 square miles. Lake Tahoe’s greatest depth of 1,645 feet makes it the second deepest lake in the United States, after Crater Lake in Oregon. The bottom of the Lake is 92 feet below the level of Carson City, Nevada.

The Lake was formed through faulting of the Earth’s crust, volcanism and glaciation.

About 25 million years ago, the Sierra Nevada block was formed by tremendous uplifting. The valley that later became the Tahoe Basin sank between two parallel faults as the mountains on either side rose. Water filled this Basin where Lake Tahoe lies today.

Lava flowing from Mt. Pluto on the north shore formed a barrier or dam across the basin’s outlet. Water from rivers and streams flowed into the Basin, gradually filling it several hundred feet above its present level.

During the last Ice Age, less than a million years ago, huge ice blocks or glaciers formed in the surrounding mountains. These glaciers scoured the landscape, carving broad, U-shaped valleys now occupied by Cascade Lake, Fallen Leaf Lake, and Emerald Bay. The material left after the glaciers melted, called moraines, blocked the original outlet of Lake Tahoe, changing it to the present Truckee River outlet at Tahoe City.

There are 63 streams that flow into Lake Tahoe and only one, the Truckee River, that flows out and into Pyramid Lake. Unlike most bodies of water in North America, Tahoe’s water never reaches the ocean.

Waters are cold in Lake Tahoe, staying a constant 39 degrees Fahrenheit below 600 feet. However, shallow areas around the Lake can warm up to 60 degrees Fahrenheit and above during the summer months.

The Lake Tahoe Basin has its share of below-freezing days and nights, but surprisingly enough the Lake itself has never frozen over. On occasion, Emerald Bay has been covered with a layer of ice, and ice also forms in cold protected inlets. However, Lake Tahoe’s great depth and volume of water is always in motion and keeps it from being the world’s largest ice rink.

Lake Tahoe’s natural rim is 6,223 feet above sea level, and its dam allows for a maximum surface elevation of 6,229 feet, making it the highest lake of its size in the United States. At any given time, its exact elevation is controlled by a dam at Tahoe City, and depends on how much water flows in from the mountains and how much is let out into the Truckee River. In recent years, prolonged drought partly fueled by climate change has caused the Lake to drop below its natural rim, meaning water ceases to flow out and down the Truckee River.

For many thousands of years, Lake Tahoe was occupied only by Native American tribes. Artifacts confirm the presence of the Washoe Tribe of Native Americans at Lake Tahoe over 10,000 years ago. Native Americans camped, hunted, and fished at Lake Tahoe in relative seclusion until General John C. Fremont’s exploration party “discovered” the lake in 1844.

For many years following Tahoe’s discovery the area was virtually ignored. In 1859 however, the Comstock Lode was discovered in Virginia City, Nevada. During the 1860s Tahoe became the center of a lively commerce involving the silver mines in Virginia City and the Central Pacific Railroad (which was pushing over the Sierra toward the town of Truckee). The Comstock era resulted in large-scale deforestation of the Tahoe Basin, as timber was required to build mine shafts and support growing developments. It is estimated that over 80 percent of the Basin’s forests were clear cut during this time.

Since then, public appreciation of Lake Tahoe and its natural resources has grown. During the 1912, 1913, and 1918 congressional sessions, conservationists made efforts to designate the Tahoe Basin as a national park but they were unsuccessful. Development pressures escalated again in the 1940s and 1950s, and a group of residents and visitors who were concerned about the environmental health of the region formed the League to Save Lake Tahoe in 1957.