Sneaky sneaker waves may creep up on beachgoers today. The National Weather Service is warning people to be alert.

“We’ll have yet another long period swell arriving along the northwest California coast today,” the NWS stated this morning. “This will likely have some set behavior, so that a risk of sneaker waves may be found along west and northwest-facing beaches by this afternoon and lasting into tonight. Be especially cautious on steep beaches today, and never turn your back on the ocean!”