Lake Tahoe's alpine waters have reached their clearest state in decades. Here's why

Now is the perfect time to plan a getaway to Lake Tahoe. The stunning crystalline waters of North America's largest alpine lake are clearer than they have been since the 1980s, according to a recent study—but this clarity might only last a few years.

Researchers at the Tahoe Environmental Research Center (TERC) at the University of California, Davis, indicate that a change in two of the lake's animal populations played a key role in enhancing water clarity. A decline in microscopic creatures called Daphnia zooplankton, which consume particles that cloud the water, coincided with a spike in their main predator, the invasive Mysis shrimp. However, the shrimp population 'unexpectedly plummeted' two years ago, as reported in the study, allowing the zooplankton to rebound and resume their cleaning duties. They consume phytoplankton, other tiny lake organisms, and minuscule clay particles, all contributors to the cloudiness. 'Essentially, they're like little Roombas tidying up the lake,' TERC director Geoffrey Schladow shared with NPR.

The research team assesses water clarity using a small instrument known as a Secchi disk, which is lowered into the lake until it disappears from view. The average annual clarity measurement improved from 61 feet in 2021 to 71.7 feet in 2022, with forecasts suggesting further increases in 2023. 'Our goal is to restore clarity to 97.4 feet,” states the EPA.

Tahoe is among the world's deepest and oldest lakes, estimated to be 2 million years old, according to the Lake Tahoe Tourism Board. Nestled in the Sierra Nevada on the border of California and Nevada, the lake has long been a favorite year-round vacation destination thanks to its breathtaking natural scenery.

Supporting the resurgence of zooplankton is a collaborative effort among hotel industry leaders in Lake Tahoe to keep the waters pristine and mitigate pollution. The Ritz-Carlton Lake Tahoe and Edgewood Tahoe Resort have joined forces with community clean-up organizations and initiatives aimed at reducing plastic and sediment.

However, scientists warn that there may be a limited timeframe for this peak level of lake cleanliness. The shrimp population is expected to rebound, and once that happens, 'Daphnia will vanish, and clarity will revert to previous levels,' Schladow noted. 'It might last for about two years, perhaps a bit longer.'