SAN FRANCISCO (BCN) — The National Weather Service Friday warned that Bay Area beaches could see strong rip currents this weekend, making the waters riskier than usual for swimmers.

A west southwesterly swell was expected to move into coastal areas between Sonoma and Monterey counties this evening, creating stronger than usual rip currents through at least Saturday evening, according to a weather service coastal hazard message.

A larger northwesterly swell will follow Saturday night, extending the danger into Sunday. Rip currents can quickly pull swimmers into deep water. They are especially common near jetties, inlets and piers.

Swimmers caught in a rip current should swim parallel to the shore to escape the current before trying to swim for shore. Whenever possible, swimmers should stay where there is a lifeguard on duty.