Lake Tahoe’s water clarity improved in 2018 mainly due to a typical winter season and water flow on rivers and streams, according to a new study. The annual report by UC Davis researchers found the average clarity level in 2018 was 70.9 feet, a 10.5-foot increase from 2017. Two years ago clarity had dropped to a record low, partially due to record-breaking precipitation and unusually warm lake temperatures. Scientists measure clarity by lowering a 10-inch white disk into the water and noting the depth at which it become invisible. They took 26 readings from January through December in 2018. Clarity is typically best in fall and winter. The winter (December to March) average was 73.5 feet, with one reading in March measuring more than 100 feet. The lowest value was 50 feet in July 2018, while the summer average (June to September) was 61.7 feet. A number of factors impact the clarity of the lake, but a primary influence is the spring runoff, the water that pours into the lake as the snowpack melts. While a winter marked by excessive snow might be good for filling the lake with water, a massive snowpack sends rivers roaring in the spring and washes more sediment into the la...