fun facts about lake tahoe

	How was the lake formed? Faulting: 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. Volcanism: 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. Glaciation: 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.
	Where does the water go? There are 63 streams that flow into Lake Tahoe and only one, the Truckee River, that flows out into Pyramid Lake. Unlike most bodies of water in North America, Tahoe's water never reaches the ocean.
	How much water is in the lake? The water in Lake Tahoe could cover a flat area the size of California to a depth 14 inches. This is enough to supply everyone in the United States with 50 gallons of water per day for 5 years. And believe it or not, the amount of water that evaporates from the surface of Lake Tahoe every year could supply a city the size of Los Angeles for 5 years.
	Why is it so blue? Because of its purity and great depth, and the clarity of the atmosphere, all colors of the sky and landscape are reflected in Lake Tahoe. You can see why it is called the "Lake of the Sky", with its brilliant shades of blues, greens, and reds. Because it is so clear, the bottom adds shades to the blue; sand reflects as light blue, rock and deep canyons as virtually black.
	How cold is the water? Waters are so cold in Lake Tahoe, staying a constant 39 degrees Farenheit below 600 feet. However, shallow areas around the lake can warm up to 60 degrees Farenheit during the summer months.
	Does it ever freeze over? The Lake Tahoe Basin has it 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.
	How clear is the water? Tahoe is so clear that in some places objects can be seen to depths of over 70 feet. One reason is that 40 % of the precipitation falling into the Lake Tahoe Basin falls directly upon the Lake. The remaining precipitation drains through the marshes and meadows, which are a good filtering system for water. Unfortunately, many of the Lake's natural filtering systems have been disturbed by development and Tahoe's clarity is diminishing. Click here to learn more.
	How large is the lake? 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 1636 feet makes it the third deepest lake in North America and the tenth deepest in the world. Crater Lake in Oregon is 1930 feet deep and Great Slave Lake in Canada is 2010 feet deep. The bottom of the Lake is 92 feet below the level of Carson City, Nevada.
	What is the elevation? Lake Tahoe's average surface elevation is 6,225 feet above sea level, making it the highest lake of its size in the United States. Its exact elevation, controlled by a dam at Tahoe City, depends on how much water flows in from the mountains and how much is let out into the Truckee River.