HALF MOON BAY, Calif. (KCBS) -- San Mateo County plans to use its community alert system to announce when the Mavericks surf contest is called.

The annual Half Moon Bay competition could be called as early as this Friday. The window of time where the world’s top big wave surfers are on call for the event was expanded this year because last year swells never reached contest size.

The alert system sends a text message to cell phones or any PDA, according to Sheriff’s Department Sgt. John Diggins.

"The system is completely free unless you have to pay for text messaging, but that depends on your carrier," said Diggins. "We've used it for road closures. It's a system I use for calling my volunteers out. We use it fairly frequently, but this is the first time we've used it for Mavericks."

About 3,700 people have signed up for the digital alert system.

Mavericks typically draws tens of thousands of spectators to the shore.