Surfers, Others Catch Wave of Forecast Data

When Hurricane Guillermo churned up the waters off Mexico 10 days ago, local boaters, fishermen and surfers already knew it would send powerful waves thousands of miles north to pummel Ventura County’s coastline.

Predicting the waves over the horizon has become increasingly easy through commercial weather and wave forecasters and free Internet sites that compile weather data and wave information.

Lifeguards at Port Hueneme Beach, for instance, already knew last weekend that they would see waves topping 12 feet by midweek.

The advance notice enabled them to issue warnings about treacherous surf and coastal rip currents, and close the surf zone to swimmers to protect the public health.

“Forecasting allows us to prepare,” said 24-year-old lifeguard Jonas White, while watching the waves churn up white water at the Port Hueneme pier. “A lot of times a predicted swell doesn’t come, but when they do, we are ready with extra people on duty.”

Such forecasting allows seafaring barges laden with expensive equipment to elude devastation.

Rea Strange, a local weather and wave forecaster of more than three decades, sized up the swells produced by Guillermo in time to warn one of his clients--a barge operator with equipment afloat near Tijuana.

The barge was moved to safe harbor, Strange said, to ride out the big seas.

For others, predicting a big swell is more sport than anything else. It can mean the difference between catching waves and catching nothing.

When Guillermo-generated surf began to crash along Ventura’s coast last week, Lee Westfall, 17, of Thousand Oaks was ready.

Westfall didn’t smell the big waves coming on the wind or feel some strange cosmic vibe. He knew the waves would be good at Leo Carrillo State Beach because the news arrived via fax.

“I knew it’d be big down there ‘cause it said it would,” the teenager said.

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Other surfers packed the lineup at Ventura’s Surfers Point because they had made a phone call, or tapped into the Internet and found out a big south swell would be hitting.

Many surfers--especially the landlocked ones--have become dependent on professional wave forecasters who offer predictions on one-sheet faxes or on recorded announcements accessible with a toll call.

WaveFax, which is the biggest of the swell forecasters, offers weather and swell predictions for California, Hawaii, Mexico and Central America for $10 a month, said Sean Collins of Surfline/Wavetrak in Orange County.

Collins has 100 surf reporters who provide updated information on conditions and coming swells on both the coasts and in Hawaii.

The company also provides a service that will call or page a subscriber when the surf’s up, Collins said.

But for cash-strapped surfers or those who are just plain cheap, there is also a slew of free services.

One is the National Weather Service’s radio broadcast, which includes information on the height and direction of waves detected by a system of buoys tethered along the California coast. Using more sophisticated sensors on an offshore oil platform, the Scripps Institution of Oceanography provides even more detailed information, along with swell forecasting on its web site.

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Ventura surfer Peter Miller, 30, said he doesn’t like the idea of paying for wave information.

“Well, I’m Scottish and I don’t like paying for anything,” Miller said.

It takes some time and experience to make sense of complicated--but free--weather maps of the Pacific Ocean covered with isobars demarcating high- and low-pressure systems and wind-flow patterns. But Miller, like many other surfers, has become something of an amateur meteorologist.

“I have in the past been tempted to spend $1.50 for a call on the Surfline, but I like to hone my skills,” said Miller, who checks several weather forecasting maps on the Internet’s World Wide Web every day.

“I can look at a couple of good maps posted on the web and pretty much tell where it will be good,” he said.

Paul Nielsen, 45, who owns Waveline Surf Shop just a block from Surfers Point in Ventura, said over time a surfer builds an almost encyclopedic knowledge of wave conditions.

“I’ll look at the Scripps Institute’s wave model and that gives you graphically a picture of wave heights and swell direction,” Nielsen said. “You look at the buoy readings and know the angle of the swell the intervals of the waves and wave height and you’re going to know what spots will be good on what tides.”

But all that time figuring out wave size, direction and timing can cut into time in the water.

“You know,” Nielsen, “when I want to go surfing, I just walk down to the Point and paddle out.”

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Web WAVE WATCH Sensors attached to an oil platform off Point Conception gather data for a wave forecasting program run by UC San Diego’s Scripps Institution of Oceanography. The information helps produce a Southern California swell model that is updated hourly. This and other results of the Coastal Data Information Program are available on the Scripps Web site on the Internet at https://odip.ucsd.edu.

SENSING WAVE MOVEMENT

Height and period: Sensors can tell the height of a wave by measuring the pressure in the water column above them. The more pressure, the bigger the wave. The period, or frequency, is known by the time difference between peaks.

Swell direction: Having an array of sensors on the platform allows the swell direction to be known. A wave reaching two sensors a the same time comes from a different direction that a wave reaching the same two sensors at different times. Eight sensors allow for more precise data.

MONITORING THE SOUTHERN CALIFORNIA COAST

Chevron’s Harvest Platform northwest of Point Conception is an ideal location because it is open to swells from the north, west, and south. Information collected there allows anyone with an interest in the ocean to stay informed. Every second, data from sensors is stored in a computer on the platform. Once an hour, computers at Scripps call to download the most recent data, which prompts the Harvest computer to transfer data by microwave to an on-land receiver and on to Scripps by telephone lines.

WEST COAST NETWORK

The Coastal Data Information Program is a cooperative project of the Army Corps of Engineers and the California Department of Boating and Waterways, with an annual budget of $650,000. These agencies contract with Scripps to oversee wave measuring networks on the East and West coasts and Hawaii. The networks--buoys and offshore and near-shore sensors--also feed information to the National Weather Service.

Buoys: These report wave height, period and direction by measuring the displacement (up and down movement) from mean sea level every second and transmit the data to onshore receivers. Buoys cost about $45,000 each.

FROM THE WEB SITE: TWO SWELLS

WEST SWELL

Most winter swells come from storms generated far north and west of California. At right, a large west swell bring 4- to 6- foot waves to most beaches, with bigger ones sneaking between the islands and hitting west-facing beaches in Oxnard and South Bay and the San Diego area.

Wave Height Scale: Coastal waters are color coded according to the height (in feet) of the waves passing through them. Reds and yellows are areas of biggest swells, blues and greens the smallest.

SOUTH SWELL

In the spring and summer, swells are usually generated to the south, often in the Southern Hemisphere. Forecasting south swells is done after the fact because swells at the Harvest platform have already hit most area beaches. At right, Hurricane Guillermo off the coast of Mexico last week is generating a moderately large south swell. Waves are in the 3- to 5-foot range in the Ventura-Oxnard area, with large sets.

Island Shadow Effects: Local coastal forecasting is affected by the large number of islands. These block the swell at beaches directly behind them (in line with the swell direction), causing waves to vary greatly within a few miles. Waves in shadow areas, at left, are about half as big as those in areas that receive the swell more directly.

Directional Spectrum: This compass, with the Harvest platform as its center point, shows the direction of swell propagation (here about 275 degrees), intensity (bright colors have the most energy and, therefore size) and period (time between swells; here about 13 seconds). The closer to center, the greater the period, meaning that the swell comes from a greater distance. Brightest blotch shows main swell.