Going down, down, down...
Lake Tahoe's water level typically rises between December and July due to snowmelt, rain, and groundwater inflow. The water level will usually fall from July through the end of the year due to a combination of water releases to the lower Truckee River and constant evaporation. But no two years are ever the same.

After a this year's dry winter, it is interesting to consider what the lake level will do between July and December. Currently the lake level is 6,224.88 ft. (WILL UPDATE THURSDAY NIGHT). Based on past July-to-December trends, the lake level is likely to fall to 6,221.8 ft by the end of this year, a drop of over 3 ft and well below Lake Tahoe's natural rim of 6,223 ft. That means by early October, no lake water will flow into the Truckee River.

Real-time and historical water level data for Lake Tahoe are provided by the USGS gaging station at Lake Forest (https://waterdata.usgs.gov/nv/nwis/uv/?site_no=10337000&agency_cd=USGS).
A shrunken Lake Tahoe can be seen in a photo comparison of the east shore, highlighting the dramatic difference between a drought year (September 2016, top image) and a lake following a large winter (July 2017, bottom image). In water year* 2016, following four years of drought, the water level dropped to 6221.58, the third lowest level ever recorded.






*The Water Year extends from October 1 through September 30
Learn how Nevada water managers are preparing for extreme drought conditions across their state at the link above.

Questions? Email tercinfo@ucdavis.edu