SALEM, Ore. — One moment, Jayson Thomas was on the Oregon beach with his 3-year-old son. The next, they were gone, swept away by a “sneaker wave” as his wife looked on.

The man and his boy were but the latest to be lost to a sneaker wave, which are prevalent in the Pacific Northwest. A leading expert says there needs to be greater awareness to prevent future tragedies.

In fact, Tuba Ozkan-Haller of Oregon State University has just finished the first year of a three-year research project to devise a sneaker-wave early warning system, a project funded by the National Science Foundation.

A sign along the trail to the beach warns of sneaker waves and high surf, though it was not clear if warning signs are posted where Thomas and his family were.

The seas off were not particularly rough on Sunday afternoon when Thomas, his wife and their son were on the beach, Ozkan-Haller noted.

But appearances can be deceptive.

“People make up their minds about how safe an area is pretty quickly … .,” Ozkan-Haller said Tuesday.

While the weather might be fine, a storm far out to sea, even across the Pacific, often generates such a wave. As it moves through the broad surf zone and over the gentle slope approaching Oregon’s coast, one wave can catch up with another, combining forces and allowing it to run up further on the beach.