Lake Tahoe Has Risen Nearly 1 FOOT In 2017 | That’s 33.6 Billion Gallons of Water

The year 2017 got off to a very busy start in the Sierra Nevada, with storm after storm bringing much-needed rain and snowfall across the region. Earlier this week we published the storm total rainfall amounts for a very impressive atmospheric river event moving through the area, but how much has Lake Tahoe actually risen as a result of all that rain and high-elevation snowmelt so far this year?

Nearly a Foot of Rise Since January 1, 2017

Since January 1st, Lake Tahoe has risen nearly a foot. In terms of volume, that translates to an increase of roughly 103,200 acre-feet, or approximately 33.6 billion gallons of water. For reference, an average household of four uses about one acre-foot of water per year — meaning the lake gained enough water in just the first few weeks of January to supply over 100,000 households for an entire year.

According to figures from the U.S. Water Master’s Office, each foot of water stored in Lake Tahoe against the dam at Tahoe City is equivalent to about 120,000 acre-feet, or roughly 39.1 billion gallons. Locals have already taken to nicknaming this stretch of relentless winter weather “Januburied” and “Snowmaggedon.”

From Drought to Deluge

The scale of this rise is especially striking given where Lake Tahoe’s water level stood just a few years earlier. The lake, which straddles the California-Nevada border, had spent much of the preceding drought years sitting well below its natural rim of 6,223 feet in elevation — at times so low that water managers feared it could take decades to refill under normal conditions. This January’s onslaught of atmospheric river storms is rapidly reversing that trend, and forecasters expect the lake’s level to keep climbing as more storms move through the region in the weeks ahead.

The lake is considered legally full once it reaches 6,229.1 feet against the Tahoe City Dam, meaning there remains substantial storage capacity even after this rapid early-January rise.

One of the individual storms driving this surge dropped nearly 136,000 acre-feet of water into the lake over the course of a single week — roughly one-third of Lake Tahoe’s entire average annual inflow arriving in just seven days.

How the Dam and Natural Rim System Works

Lake Tahoe’s water level is managed through a dam at Tahoe City, originally built in 1870 as a rock-filled crib structure to help power lumber mills and float logs down the Truckee River. When the lake’s level rises above its natural rim of 6,223 feet, water can continue to be stored behind the dam up to the legal maximum of 6,229.1 feet. Beyond that point, dam operators release water downstream into the Truckee River to keep the lake’s elevation under control, and releases are also made periodically throughout the season to manage the rise proactively rather than waiting until the lake nears its limit.

Why a Wet Winter Matters for the Region

Terri Edwards, Area Manager of the Lahontan Basin Area Office, has said water managers expect a wet year overall and may even need to spill water at several regional reservoirs to keep up with the inflow. For a region that had spent years grappling with drought conditions, a winter capable of adding tens of billions of gallons of water to Lake Tahoe in a matter of weeks represents a dramatic and welcome turnaround — one that could also set the stage for a historic ski season if the pattern of storms continues through the winter.

Lake Tahoe has seen major flood events before; the last comparable atmospheric river-driven flood struck the basin in 1997, following a string of heavy snowstorms that year. While this rise doesn’t approach that historic flood, it’s a clear early-season sign of how quickly conditions in the Sierra Nevada can shift from drought to abundance when the right storm pattern sets up over the region.