Lake Tahoe is Fullest for Two Decades | Heavy Snowmelt Means it’s Approaching Legal Limit

SnowBrains |
Lake Tahoe, clarity, tahoe, California, Nevada,
Lake Tahoe’s legendary clarity amazes the 3-million annual visitors. Credit: Tim Peterson | Unsplash

Lake Tahoe is the fullest it’s been in nearly two decades and is approaching its legal limit after snowmelt from a heavy winter left enough water to potentially last through three summers of drought, reports the SFChronicle.

If you were to pour Lake Tahoe out onto an area the size of California, the water would be 14 inches (36 cm) deep.

For the last three weeks, Tahoe has been within less than an inch of its maximum allowed surface elevation of 6,229.1 feet above sea level, and in the last week even rose to within a half-inch.

Chad Blanchard, a federal water master in Reno responsible for managing the water, told the Reno Gazette Journal it’s the longest he’s seen the lake stay that high for so long.

“This is a rare year,” he said. “I’ve been doing this for 26 years, and we’ve had big (snow) years, but this one is unique as far as being up within an inch of being full and it’s just hanging there … It’s a product of still having so much snow up there.”

As winter snow continues to melt from mountain tops and into Tahoe, the rate of summertime surface evaporation is beginning to pick up. Blanchard added that the lake soon will reach a point of equilibrium when snowmelt slows and the rate of evaporation increases. Then, the lake level will begin to drop.

The legal limit of the lake plays a role in determining if, when and how much water is spilled into the Truckee River at a dam in Tahoe City, California. This summer will be the third time in the past three years that the lake has come up to the edge of its legal limit. That previously happened in 1998, 1999 and 2000.

Lake Tahoe raging through the Lake Tahoe dam into its only outlet, the Truckee River on May 25th, 2017 photo: snowbrains

Squaw Valley saw 715″ of snowfall this season – they average 450″ of snowfall.

In the past 30 years, Lake Tahoe has fluctuated between 6,220.26′ and 6.229.39′.  That high mark being the 1997 flood. The idea of a legal limit dates back to 1907 and 6,229.1 feet was established as the upper, or legal, limit of the lake around 1917.

In December 2016, Lake Tahoe was sitting at only 6,223.04′.  


  • The water is 99.994% pure, making it one of the purest large lakes in the world. For comparison, commercially distilled water is 99.998% pure.
  • Lake Tahoe is the largest alpine lake in North America, and at 122,160,280 acre·ft (150,682,490 dam3) trails only the five Great Lakes as the largest by volume in the United States.
  • Its depth is 1,645 ft, making it the second deepest in the United States after Crater Lake in Oregon (1,945 ft).
  • Lake Tahoe is over 2 million years old. Tahoe is considered an ancient lake and is counted among the 20 oldest lakes in the world.
  • The amount of water that evaporates from the Lake each day (330 million gallons) could supply a city the size of Los Angeles for 5 years.
  • If you were to pour Lake Tahoe out onto an area the size of California, the water would be 14 inches (36 cm) deep.

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