A coastal flood advisory covering the San Francisco Bay shoreline, including Burlingame, runs through 5 p.m. Thursday, Oct. 1, with tides forecast to hit 1.2 feet above normal.

The National Weather Service (NWS) issued the advisory as remnants of Tropical Storm Odalys and Hurricane Polo push swells toward the California coast. "Those ocean swells are tied to the presence of Hurricane Polo," NWS meteorologist Matt Mehle told the Mercury News. The hurricane had been moving north toward Mexico's Baja California peninsula.

NWS meteorologist Dial Hoang told Local News Matters that high tides through Wednesday, Sept. 30, are forecast to be about 1.2 feet above normal, bringing a chance of flooding to low-lying coastal areas from Marin County south to Monterey County.

The elevated tides could flood lots, parks and roads, cut off access to some beaches and push waves farther up the shore than usual, the Mercury News reported, citing the NWS advisory. The advisory took effect at 11 a.m. Monday, Sept. 28.

The San Francisco Chronicle reported that the Bay Area NWS office had never issued a coastal flood advisory in September before this year. This is the second coastal flood advisory issued in September. Sea levels along the California coast are running 6 to 9 inches above the late-20th-century baseline, driven by long-term warming and a strong El Niño, the Chronicle reported.

Pacific surf warning also in effect

Separately, the NWS issued a high surf warning for Bay Area coastal waters through Thursday, Oct. 1. The warning applies to the Pacific coast, not the Bay side.

San Mateo County Parks said its facilities on both the Pacific and Bay sides of the peninsula will stay open but urged visitors to keep a cautious distance from the surf. The department warned that coastal bluffs can become unstable with increased water saturation.

In a standing safety advisory, the county parks department noted that bluffs may become unstable during and after wet weather and advised people not to walk on beaches directly below bluffs.

Safety tips

The NWS advised drivers to allow extra time, avoid driving around barricades and not to cross water of unknown depth. San Mateo County Parks urged beachgoers to:

  • Stay well back from the surf line.
  • Avoid the edges of coastal bluffs.
  • Stay off beaches directly beneath bluffs.