SAN FRANCISCO— The Coast Guard warns vessel owners, operators, and beachgoers of high surf and winds affecting the Bay Area Thursday and Friday. Sixteen to 22-foot waves are expected at beaches from Point Reyes south to Big Sur. Small craft advisories are in effect for San Francisco Bay, Monterey Bay, and the offshore waters from Point Arena to Point Piedras Blancas. Beachgoers are advised to use extreme caution when near the water. Large waves can impact the beach with little or no warning and drag a person offshore in a matter of seconds. Swift and strong undercurrents combined with cold-water temperatures make it nearly impossible to survive. The Coast Guard recommends that during this period of high surf, beachgoers remain well clear of the beach foreshore where waves make landfall.In the event that your vessel or someone aboard your vessel is in distress, call the Coast Guard on VHF/FM Channel 16, or call the Coast Guard Sector San Francisco Command Center at 415-399-3451. If you see someone get swept out to sea, do not attempt to rescue him or her by entering the water - call 911 immediately.Please visit the National Weather Service's web page at http://www.wrh.noaa.gov/ for specific information regarding the exact times and locations these advisories are in effect.