The next time you check a surfing webcam to see if the waves are worth a trip to the beach, scientists might be checking it too — but for something completely different. Researchers at the University of California, Davis, and the USDA Forest Service have discovered that ordinary surfing webcams can help track fog along Oregon's coast, offering a simple new tool to study a phenomenon that shapes everything from beach days to forest health.

Fog is not just an annoyance for beachgoers. Along the Oregon coast, summer fog provides vital moisture to ecosystems and eventually feeds into rivers and groundwater. "Fog is a cloud that literally touches people's lives and also impacts ecosystem health," said Sonya Rauschenbach, a graduate student at UC Davis who led the study. "It's a direct input into the water system here."

Traditional fog measurement relies on satellites or expensive instruments, both of which have drawbacks. Satellites struggle to distinguish fog from low-hanging clouds, while precise sensors are rare and costly. So Rauschenbach and her team asked a simpler question: could the webcams surfers already use to check wave conditions double as fog detectors?

Over three summers, from 2022 through 2024, the researchers collected daytime images from five surfing webcams across 93 miles of Oregon coastline. The cameras sat at Agate Beach, Otter Rock, Pacific City, Lincoln City, and Cannon Beach. The team also analyzed a long-term image database from Oregon State University at Yaquina Head. They compared what they saw on the webcams with official weather measurements from the Newport Municipal Airport, where a visibility sensor records fog conditions.

The findings revealed something surprising: fog along Oregon's coast is surprisingly spotty. "I thought I kind of knew its spatial patterns, but I've been surprised by how low the correlation was between some sites," said co-author John Kim, a scientist with the USDA Forest Service. "I think that's helpful to know for the beachgoing public and deepens the mystery for fog scientists."

Typically, fog appeared at only one site at a time, shifting rapidly over short distances. An airport weather station might report clear conditions, while a beach just a few miles away sat wrapped in gray. The webcams could generally tell whether fog was present, though they could not precisely measure exactly how thick the fog was.

The researchers say the study, published in the journal Agricultural and Forest Meteorology, is the first to examine how fog varies across space along the Oregon coast using webcams. Understanding these patterns matters more as climate change alters fog frequency in ways scientists are still working to predict.