The clarity of Lake Tahoe’s cobalt blue water improved dramatically in 2018, a year after the combined forces of historic drought and record-breaking rain resulted in the lake’s lowest visibility levels since record-keeping began in 1968.
Scientists measure water clarity by lowering a 10-inch-wide white disk into the lake and noting the lowest point at which the disk remains visible. In 2017, the disk was visible at an average depth of 60.4 feet — an all-time low.
But the lake bounced back in 2018. The average clarity from 26 readings taken throughout the year was 70.9 feet, according to the UC Davis Tahoe Environmental Research Center. The annual findings are typically released in the spring after the university analyzes the data it gathers each month in the previous year.