Lake Tahoe - How Low Will It Go?

The Reno / Tahoe dry spell continues, with a slight, but inconsequential, break. After 70 days without rain and what may pencil out to be the warmest September on record, the National Weather Service recorded 0.01" at Reno Tahoe International Airport on Monday, September 29. Rain is forecast for Friday and Saturday, but I'll believe it when I get wet. I learned long ago that most weather prognostication around here is iffy, though I don't fault the weather guys. Our combination of high desert, high mountains, and dueling air masses makes for some unusual and rapidly changing conditions. Weather stuff sometimes sneaks up on us unannounced.

A stark symptom of the dry conditions is Lake Tahoe's level, which is dropping ever closer to its natural rim. When that happens, water will cease flowing into the upper Truckee River from Lake Tahoe. Downstream users like Reno and Sparks will then depend on mountain reservoirs, such as Boca and Stampede, to maintain river flows. Water from wells around the Truckee Meadows will also be tapped by the Truckee Meadows Water Authority to meet municipal demand.

Lake Tahoe Dam, completed in 1913, was built to raise Lake Tahoe's level by six feet, to store and release water for downstream use. The dam, at Tahoe City, CA, on Lake Tahoe's west shore, is at the lake's only outlet. Once the water level reaches its natural rim, the ability to control water releases into the Truckee River ceases to exist and downstream reservoirs, also built to store water and control flows, come into play. On September 24, the lake level was 6223.8 ft., according to the North Lake Tahoe Bonanza. That's about eight inches above the natural rim. So far, things related to water are reasonably okay on the Nevada side. That will change if this winter is the third in a row of below average precipitation. In California, Gov. Arnold Schwarzenegger proclaimed a drought way back in June. It's time to start dancing, or praying, or whatever you do to try and invoke some seriously heavy snowfall this winter.