Local water authorities hope for snow to fill up lake

With Lake Tahoe’s water level nearing the natural rim, water authorities are hoping for record-breaking precipitation to bring the water level up.

“We really desperately need a big winter and a big snowpack to bring Lake Tahoe back up again,” said Federal Water Master Garry Stone.

When the water in Lake Tahoe nears the natural rim, which is 6223 feet, water flows less quickly into the Truckee River.

As of Wednesday night the lake measured at 6223.25. Normally there are about 250 cubic feet per second running into the Truckee. Right now the rate is about 12 cubic feet per second, Stone said. If the lake level drops below the natural rim no more water will flow into the Truckee.

“We can’t get any more water out of it,” Stone said. “It’s like a bathtub, we do not have the ability to release water through the natural rim.”

After that water from Boca Reservoir and smaller natural streams will flow through the Truckee.

Stone said there is enough water in Boca to supply the river until sometime in December.

While the level of the lake does not affect water supply at the towns and villages in the Basin, it does affect other areas like Reno, Stone said.

For his part, Stone said ideally the region would experience a winter with three or four times the average snow pack to bring the river above the natural rim and to an acceptable level.

“It’s a very tenuous situation,” he said.

The average precipitation for the Tahoe area in the winter is 31.77 inches, said Jim Ashby, a service climatologist with the Western Regional Climate center. In the past 100 years, only two winters have topped 60 inches of precipitation, the winter of 1981-1982 with 64.25 inches and the winter of 1994-1995 with 61.21 inches.

“Those winters are pretty unusual,” he said.

The level of snowpack Stone would like would be unusual and unprecedented, said Dan Greenlee, a Water Supply Specialist with the Natural Resources Conservation Service.

“We’d be buried from here until next July Fourth,” he said.

The amount of water yielded from a snow back depends on the density of the precipitation Greenlee said. While soft powder is great for skiers and snowboarders, dense snow or Sierra Cement is better for revitalizing the lake, Greenlee said. That means snow that comes down at warmer temperatures, between the mid to high 20s.

“As it cools down the snowflakes hold less water,” he said.

Although this year’s fall has been mild according, anything could happen this winter, he said.

“It’s not untypical to have no snow at these sites,” he said. “You can’t tell what’s going to happen at this point in the year.”

Still, rain earlier this fall may help the lake fill as snow will fall on moist ground, said Randall Osterhuber, a snow hydrologist at the U.C. Berkeley Central Sierra Snow Laboratory at Donner Pass. Still, like Stone, Ashby and Greenlee he said the weather is unpredictable.

“I know everyone wants an answer to what the winter is going to be like but even the long range forecasts are so vague it’s not even worth considering,” he said.