Decade’s Highest Tide May Cause Coastal Flooding

High tides caused minor highway flooding Monday morning at Sunset Beach in Orange County and worried coastline property owners throughout the Southland--but that was only a taste of what may be in store on New Year’s Eve, when the highest California tide of the last decade will occur.

Monday morning’s tide was 7.1 feet along Los Angeles, Orange and San Diego counties’ coastlines, pushing 3 to 4 inches of water from Huntington Harbour into the northbound lanes of Pacific Coast Highway at Sunset Beach.

Seawater spilling onto the highway between Huntington Beach and Seal Beach slowed morning commuter traffic for two hours along a three-mile stretch of roadway.

Traffic Snarled

Between Warner Avenue in Huntington Beach and the bridge over Anaheim Bay in Sunset Beach there were signs warning that the highway was flooded, but all four lanes were open. Seawater was about three or four inches high at the curb of the road, but “none of the travel lanes were flooded,” Huntington Beach city engineer Les Evans said.

“However, there was enough flooding to make people drive more slowly, and it backed up traffic starting around 7 a.m. and ending around 9 a.m,” Evans said.

The California Department of Transportation announced that it will close one lane of the highway between 7:30 a.m. and 10 a.m. today, when a 7.2-foot tide will occur at 8:40, and Wednesday, when the tide will rise to 7 feet by 9:30.

In Newport Beach, several streets on the Balboa Peninsula were flooded Monday, but there were no reports of property damage, according to city engineer Don Webb, who called the watery streets a routine occurrence. “When tides are above a certain level, sometimes we do get water in the streets,” he said.

There were also reports of water on Pacific Coast Highway at Malibu, but a sheriff’s station deputy said a patrol officer was unable to find it.

In San Diego, Monday morning’s 7.1-foot tide carried surf to the seawall at Mission Beach. Lifeguards moved trash cans onto the boardwalk in anticipation of a 7.8-foot tide at 8:48 a.m. today.

Celestial Events

The increased tides this week, at the end of December and at the end of January are the result of two celestial events known as perigee and syzygy, which were first recognized by Fergus J. Wood, a retired National Ocean Survey meteorologist. The survey is a branch of the National Oceanic and Atmospheric Administration.

Perigee is the point at which the moon in its irregular orbit is closest to Earth, a position that strengthens the gravitational pull that causes tides.

Syzygy refers to the near-alignment of the sun, moon and Earth, which also causes an increase in tides.

When perigee and syzygy occur close together, their effects are combined and record tidal surges can result.

The Dec. 31 tide will average about 7.5 feet along the state’s coastline, according to the National Ocean Survey.

That tide may not cause any significant flooding on its own, even in low-lying coastal areas, unless an offshore storm occurs at the same time, in which case flooding could be severe, experts caution.

On Dec. 31, perigee and syzygy will be four hours apart. High tide along beaches in Orange and in Los Angeles counties will be 7.3 feet about 8:30 a.m.

In San Diego, high tide on New Year’s Eve will be 7.8 feet; in San Francisco it will be 7.4 feet.

On Jan. 29, high tide in Orange and Los Angeles counties will be about 7.1 feet.

Tides should not be confused with sea level. Tides are the up-and-down motion of waves caused by the gravitational interaction between the Earth, moon and sun. They are “absolutely predictable,” according to oceanographer Reinhard E. Flick of the Scripps Institution of Oceanography. Sea levels are affected by wind, rain and other meteorological factors.

In January, 1983, a high tide combined with an offshore storm produced the worst flooding in Orange and Los Angeles counties in 20 years, resulting in damage estimated at more than $3 million.

Sea level at the time was about nine inches above normal as a result of El Nino, a major warming of water and winds in the tropical Pacific, and that further magnified the effects of the high tide, according to Wood.

15-Foot Waves

On Jan. 26, 1983, the storm dumped as much as five inches of rain at many sites between the Oregon border and San Diego, and pounded oceanfront communities with waves as high as 15 feet. Santa Monica’s municipal pier was heavily damaged, as were the Seal Beach Pier in Orange County and the Crystal Pier in San Diego. Waves washed out much of the beach in San Clemente.

More than 400 homes sustained minor to heavy flooding damage along the county’s northern coastline, and hundreds of residents spent the night at emergency shelters.

The Seal Beach Pier was destroyed by another storm in early March, which also caused serious damage to piers in Huntington Beach and San Clemente. The Seal Beach Pier was rebuilt at a cost of $2.3 million and reopened in January, 1985. The rebuilt version was made three feet higher to guard against destructive seas.

About 750 residents were evacuated from homes in Seal Beach and Sunset Beach because of severe flooding during the January storm. Streets and homes also were flooded in Malibu, Venice, Playa del Rey and the King Harbor area of Redondo Beach.

Storm and tide damage also was in evidence in December 1982, when pounding surf caused severe damage to nine mobile homes in El Morro Cove north of Laguna Beach. High tides of 7 feet and heavy surf also took their toll in 1967 and 1976, with flooding in Newport Beach and Sunset Beach and about a foot of water on Pacific Coast Highway in Huntington Beach.

In March, 1962, perigee and syzygy were only 31 minutes apart, according to Wood. A major storm occurred in the Atlantic Ocean at the same time, producing more than $500 million in coastal damage from South Carolina to Maine and killing 40 people.

People who live in the areas affected by the 1983 storm “should stay alert to the weather predictions,” Wood said. “If there is a strong onshore wind or major storms offshore, there is a good chance that flooding could occur again.”

The next time such high tides will be caused by perigee and syzygy will be Oct. 14, 1989.

Times staff writers Andy Rose and Lanie Jones contributed to this story.