In Hot Water : Ocean Warms Up Dramatically This Summer

When San Clemente lifeguard Richard Chew looked at the thermometer, he couldn’t believe it. It read 79.9 degrees. Not the air. The water temperature.

“We wondered if our thermometer was working right!” Chew exclaimed.

So Chew and his colleagues checked the reading against one taken by state lifeguards the same day, Aug. 18, aboard a boat a mile out from San Clemente. That reading: 80 degrees.

For at least two weeks, Orange County’s coastal waters have heated up to unusually tropical temperatures.

Last year at this time, water temperatures averaged 70 degrees, but ocean water temperatures are now averaging 76 degrees along Orange County’s coastline.

It seems that as inland air temperatures have soared, the heat--combined with only mild wind--has had a warming effect on the ocean, said Dean Jones, meteorologist for WeatherData Inc., which provides forecasts for The Times.

Jones said a high pressure system over Southern California has prevented high winds from developing over ocean waters and producing upwelling, when warmer, surface waters are moved away and replaced by colder water down below.

When told about the 80-degree temperatures, Jones said, “Wow! That is warm.”

“If you don’t have that strong offshore flow pattern, which would result in upwelling,” Jones said, “the water can become more stagnant and heat up over a period of days or weeks, even a month. And it has been a pretty warm summer.”

For lifeguards, there are other more obvious indicators of warmer waters, including larger beach crowds and more reports of stingray and jellyfish stings.

According to Chew, during a one-week period in 1993, water temperatures in San Clemente averaged 69.5 degrees. This year, Chew said that for the same week’s period, Aug. 15 to 21, the water averaged 74.9.

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“That’s almost five degrees warmer than last year and the 80-degree temperature was about the warmest anyone can ever remember it being down here,” said Chew, who has been a lifeguard for more than two decades.

Michael Mullin, professor of biological oceanography at Scripps Institution of Oceanography in La Jolla, said a research vessel that recently spent two weeks at sea found that the region’s water temperatures were cooler, not warmer.

“The implication is that although near-shore waters are warmer,” Mullin said, “the offshore region is cooler than the long-term average. . . . It’s a coastal rather than a California current-wide phenomenon.”

The California current runs north to south and skirts near shore at Point Conception then travels west of the Channel Islands near Oxnard in a band 100 miles wide, Mullin said.

“A real indicator of warm water coming up from the south are crabs, red crabs about the size of your thumb,” Mullin said. “You would see them wash up on the beach.”

Obvious indicators for lifeguards have been huge crowds of people at the beach escaping Southern California’s sweltering weather, and higher incidents of swimmers being stung from jellyfish and stingrays.

During a one-week study, Don Ito, state park superintendent in Huntington Beach, said they had to close Bolsa Chica State Beach on a warm weekend, something the state parks system had not done in recent times.

“We had a 40% increase in the number of people using our beach from the same one-week period in 1993,” Ito said.

As for stingrays, which prefer warm, placid water, Seal Beach and Huntington State Beach have reported more contacts with the bottom dwellers, according to Thomas W. Barnett, San Clemente State Beach lifeguard supervisor.

He said he also has noticed more jellyfish, which visit during spells of warmer water.

“We get maybe 72 degrees around here and that’s about as high we get,” Barnett said. “And we’re getting temps in the high 70s. I’ve never heard of it being that high around here.”

Warming Trend

Ocean temperatures along the Orange County coast have been unusually high. San Clemente’s recorded 80 degrees is the warmest in two decades. A comparison of high and average water temperatures during the first weeks of August in 1993 and 1994.

August, 1993 August, 1994 Beach High Average High Average Huntington Beach 70 67 75 71 Laguna Beach 74 70 78 74 Newport Beach 71 69 75 73 Seal Beach 72 68 77 72 San Clemente 72 69 80 73

Source: Individual beaches