Where there’s smoke, there’s not necessarily fire.

Wildfire smoke, sometimes drifting from hundreds of miles away, touched nearly every lake in North America for at least one day per year from 2019 to 2021, according to a study from the University of California, Davis. 

As much as 70% of California was covered by wildfire smoke during parts of 2020 and 2021, according to a study from the University of California, Davis. The study, published today in the journal Communications: Earth & Environment, combined lake-based sensors with satellite imagery to find that maximum smoke cover has increased by about 116,000 square miles since 2006.

How small mountain lakes spend their winters is largely unknown to scientists, despite winter representing nearly half the year in such environments. A study by the University of California, Davis, helps demystify what happens above and below the ice.