Officials demonstrate water rescue at San Francisco's Ocean Beach

SAN FRANCISCO (KGO) -- Just about the coolest spot in the Bay Area is San Francisco's Ocean Beach. Though the sun is shining, the water is more dangerous than it appears.

Rescuers demonstrated on Tuesday what happens if they have to go in after you.

High above the crashing waves, a lone firefighter stood atop a ladder with an orange flag, signaling as rescuers dive into the surf. "We enter the water, running and dolphin diving, then we'll put on swim fins, turn around and start swimming to the victim," National Park Service Ocean Rescue Supervisor Doug Armstrong said.

The victim, or victims in this case, are trained rescuers themselves. It was a mock rescue to demonstrate the ferocious conditions swimmers can face here at Ocean Beach.

"Look behind you, there are no lifeguard stands. We're not trying to promote swimming out here due to the dangers of the water," SFFD Asst. Deputy Chief Rudy Castellanos said.

Ocean Beach is known for its rip currents. Last month, a UC Berkeley professor who studies them showed ABC7 News how to escape if you're caught in one.

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"Let the current take you out. It'll probably take you out beyond the breakers. Look for the shore, swim parallel to shore, and then surf the waves back in," UC Berkeley Professor Francis Smith said.

Rip currents are often found where the waves look the calmest.

The beach patrol combs the shoreline on days like Tuesday, telling out-of-town visitors to beware. "It's more than just rip currents. We have tsunami hazards. We have sneaker wave hazards. We have high surf hazards," National Weather Service's Ryan Garcia said.

And the water is a chilly 55 degrees almost year-round. "Without the proper equipment, wet suits or life jackets, it's very easy to succumb to the cold water extremely quickly," SFPD Sgt. Dan Laval said.

Of course, rescuers hope they'll never have to swim out to get you, but if they do, time will be critical. That means whoever calls 911 will need to direct them to the right spot.

"Being able to quickly tell the dispatcher that exact location is imperative," San Francisco Dept. of Emergency Management's Kristin Hogan said.

Dispatchers will ask the caller for the number of the closest stairwell. They'll also call the Coast Guard.

Of course, if you're kite surfing or kayaking, a small marine radio will let you call them yourself. "And just in the last couple of months, we've had some cases where that made the difference between us finding a kite surfer or not," U.S. Coast Guard Capt. Tony Ceraolo said.