Double whammy of high tides, rain could flood coastal areas

The highest tides of the season will arrive in California this week in tandem with forecast rain, a powerful combination that could lead to coastal flooding.

The so-called king tides occur twice a year when the gravitational forces of the sun, Earth and a full moon align. The ocean is expected to surge starting Wednesday and peak at its highest level Thursday morning. If the waves meet ocean-bound runoff from the expected rains, there could be flooding.

Coastal communities, especially low-lying stretches of Orange County, San Diego and the San Francisco Bay Area, are readying pumps and sandbags and preparing to seal tide valves to keep the high water at bay, while environmental groups across the state plan to use the extreme tides to illustrate the potential impacts of rising sea levels.

Workers at Turcs, a bar in the north Orange County community of Sunset Beach that sits just a few feet above sea level, are set to pile sandbags in front of their doors to keep the establishment dry. It’s a precaution they take every time high tides coincide with rain, an event that overwhelms the area’s drainage system and sends sheets of water across Pacific Coast Highway.

“Come January and February, we kind of know to expect it,” said Joy Monaghan, a bartender.

Environmental groups say the king tides offer a preview of what to expect in California as sea levels continue to rise and put the coastline at greater risk of inundation and storm damage. As the ocean swells higher in the coming decades, environmentalists and others expect that tides spilling over sea walls, flooding oceanside highways and splashing up toward oceanside homes and businesses will become regular occurrences.

King tides “provide us a glimpse of what might happen and also give us an opportunity to think about how to adapt to the inevitable,” said Liz Crosson, executive director of Santa Monica Baykeeper.

Baykeeper and environmental groups across the state plan to use the high-tide event to catalog and document the areas most vulnerable to coastal flooding and storm damage, including Sunset Beach, the peninsula and islands of Newport Beach, Broad Beach in Malibu, San Diego Bay and Crissy Field and Treasure Island in San Francisco.

The California Coastkeeper Alliance is asking the public to submit photos of the effects of the high tides on beaches, roads, seaside parks and sea walls throughout the state.

The double wallop of a storm and extreme tides has soaked the most exposed stretches of coast in the past.

A storm during an unusually high tide in 2001 flooded oceanfront campsites in Ventura County and sent water bursting through a giant sand berm built to protect the Seal Beach neighborhood of Surfside.

In 1983, the water surged so high in Surfside that people had to resort to paddling boats through the streets.

For the gondoliers of Sunset Beach, which abuts Huntington Harbour, the king tides mean little beyond having to adjust their routes to avoid bridges that will probably be blocked by high water.

But there is one way Sunset Gondola owner Tim Reinard hopes to milk the occasion for some publicity: by rowing one of his boats right up next to the town’s main thoroughfare.

“We may be able to pull off having a gondola on PCH,” he said, “if it’s a high enough tide.”

tony.barboza@latimes.com