Forecasters Warn of Storm Tides : Weather: Beachfront property owners are cautioned on flooding, erosion from five- to eight-foot waves this weekend. Up to an inch of rain is also expected.

With the season’s first large Pacific storm heading for California, a wave forecaster has warned county emergency officials and lifeguards to expect high tides and five- to eight-foot surf this weekend.

“Beachfront property owners . . . may see some flooding and coastal erosion,” according to Sean Collins of Surfline/Wavetrak, a private firm in Huntington Beach. “The large west-northwest swell will be arriving on top of a seven-foot high tide around 7 a.m. on Saturday and Sunday.”

The warning, issued in a fax bulletin to agencies in Orange County, described a large storm developing in the Gulf of Alaska that may bring up to one inch of rain. Already, swells are higher than normal out at sea, because a small vanguard of the storm has reached this area.

“We’re anticipating the storm’s arrival, but don’t expect major problems,” said Larry Paul, the Orange County Environmental Management Agency’s manager of coastal facilities.

The Environmental Management Agency’s coastal supervisors met Tuesday to discuss preliminary reports about the storm’s activity. A supervisor will monitor the 6 1/2 miles of county-owned coastline this weekend to determine whether crews are needed to help prevent erosion and save property.

“We’ll deploy what we need to, based on what we see,” Paul said.

Already, the first of a series of storms has brought heavy rainfall and snow to Oregon and Washington. In Northern California, the U.S. Coast Guard in Crescent City was on a weather watch Wednesday, monitoring 50-knot winds.

“We have 25- to 30-knot winds and severe . . . rain squalls,” according to Petty Officer Jeffrey Dale, a Coast Guard spokesman in Humboldt Bay. “Our station in Crescent City is having 50-knot winds. And there are unconfirmed reports that Oregon is experiencing 90- to 100-knot winds.”

It is the storm-generated winds that are crucial to predicting whether any damage might occur along Orange County’s 42-mile coastline this weekend.

“We know a big groundswell will be here,” said Chris Borg, a meteorologist with Surfline/Wavetrak. “Also, we know we’re expecting high tides in the morning hours. If the storm develops close to shore, there’s a potential for problems with high winds that help push the waves on shore.”

Borg said he and Collins have been tracking the storm in the eastern Pacific. On Wednesday, it was about 1,500 miles from Orange County.

“The heart of the storm will track over the state of Washington,” Borg said, “but a cold front will trail out of the center, and it will track into California.”

Steve Pryor, a meteorologist with WeatherData, which forecasts weather for The Times, said the storm has struck the Northwest with fury.

“And, there are indications of lightning, which is not surprising for this kind of a system,” Pryor said.

On Wednesday, the National Weather Service, which had no forecast beyond today, reported a seven-foot northwest swell at sea from Point Conception to the Mexican border, an early indication of early storm activity.

Locally, there were two-foot seas and four-foot swells for the inner waters, according to Pryor.

“We don’t have sophisticated equipment to forecast waves and their effect,” Pryor said. “It needs to be followed closely, especially with the concern for big waves and high tides.”

Seal Beach Lifeguard Lt. Steve Cushman said his agency became concerned after receiving the warning from Collins.

“This doesn’t sound like one of the big storms, but I remember when we lost the pier here in ‘83,” Cushman said. “It was so windy that when I walked out on the base of the pier to look, I had to lean way forward.”

High winds, Cushman said, drive the high tides up a foot to two feet and, depending on the size of the surf and angle of the swell, can add another three feet to large breaking waves.

In Laguna Beach, additional lifeguards have been placed on standby, said Laguna Beach Lifeguard Lt. Mark Klosterman.

“When we have a predicted dangerous situation coming up, we let our additional personnel know and put them on standby. The next step is deployment,” Klosterman said.

In the past, Klosterman said a combination of high tides and large surf has pushed water over a seawall in the Blue Lagoon area, north of Aliso Beach, where it damaged glass windows of beach homes.

Sensitive areas also include Seal Beach, Surfside, Sunset Beach, El Morro Beach Mobile Home Park, northern Aliso Beach, Capistrano Beach and Salt Creek and Huntington Beach bluffs.