Lake Tahoe's Levels Could Change Quickly This Fall
Tahoe's level is still more than five feet above its natural rim and less than a foot from its legal limit.
Last winter brought a record amount of precipitation to the Sierra, filling Lake Tahoe almost to the brim. Several feet of water were also released from the Tahoe City Dam to make room for the snow melt. The lake is still in good shape as fall approaches. Tahoe's level is still more than five feet above its natural rim and less than a foot from its legal limit.
"It's obviously a good place to be for water supply," Chad Blanchard, U.S. District Court Water Master said.
The lake's level has only been this high 12 other times. If the Sierra has a repeat of last winter, Blanchard says it would be a welcome sight as long as it comes in the form of snow.
"It's going to be a lot of work and high flows but I'll take another big winter," Blanchard said. "Hopefully, not as big as the one we just came out of."
A rainy winter would cause Lake Tahoe's elevation to fluctuate much faster. With less available space in the lake, the Water Master would have to be creative and flexible.
"We have to go down the path of being able to fluctuate and make increases in releases to start passing water if we get wet, to be able to store water if we're dry and make sure that we have maximum water supply for next year," Blanchard said.
Water releases would mean higher flows in the Truckee River and more water for reservoirs and Pyramid Lake. The difference is last winter's precipitation happened when the area's reservoirs were nearly empty.
"If we got another winter like that, it would be a tremendous amount of water that we'd have to pass through the system and there could be some issues as far as flows," Blanchard said.
Lake Tahoe's levels usually drop during the fall months until December when it evens out. The lake has only risen six times since record-keeping began, including last year. The reason it usually drops is because there is more evaporation than inflow.
"When the cold air comes in, and the air temperature is less than the water temperature, you get this energy release into the atmosphere and with it goes water vapor and you get really large evaporation events," Blanchard said.
Blanchard says there is no way to tell what the winter will bring. The best-case scenario would be a snowy winter but he says anything can happen.
"It could be the wettest year ever. It could be the driest year ever," Blanchard said. "Probably somewhere in between but we don't know that and we just have to kind of play the waiting game and see how it plays out."
The levels of Boca, Stampede and Prosser Reservoirs are also changing. Water is being released, switching their uses from storage to flood control.