A 2006 California heat wave killed nearly 200 people. (Photo: NOAA)

(Bloomberg) — Residents of Southern California and the Southwest were looking for a break after some of the hottest weather in decades had utilities warning of potential power failures and cities opening pools and cooling centers to those in need of relief.

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At least four hikers died in Arizona, where on Sunday Phoenix set a record for the date of 118 degrees Fahrenheit (48 Celsius), AccuWeather Inc. reported. It was 109 in Burbank, California, on Sunday, besting the mark set in 1973, and temperatures there reached another daily record of 108 at midday Monday, the first day of summer.

The National Weather Service posted excessive heat warnings across Southern California, southern Arizona and into central Utah. The heat was forecast to begin tapering off Tuesday.

“It’s going to cool off noticeably,” Ken Clark, a meteorologist at State College, Pennsylvania-based AccuWeather, said in a telephone interview. Many places in the Los Angeles basin area are going to be 10 to 15 degrees cooler, he said.

Conservation urged

California’s main grid operator called on residents to turn off unneeded lights and avoid using major appliances to prevent blackouts. Los Angeles and other cities opened public libraries and senior centers to those in need of cooling. In Riverside, the city started operating water splash areas in public parks that had been shut because of an unprecedented drought that the region has been battling in recent years.

The heat wave will be the first big test of the Southern California grid after a historic natural gas leak that resulted in constrained supplies of the power plant fuel. The state has warned that the region risks as many as 14 days of blackouts this summer due to the leak. The use of Sempra Energy’s Aliso Canyon storage facility has been restricted since methane spewed uncontrollably from a broken well for nearly four months starting in October.

“We are confident we have a strong plan in place to meet the operational challenges posed by the upcoming hot temperatures,” California Independent System Operator’s chief executive officer, Steve Berberich, said in a statement. “Conservation efforts by consumers are key to reducing stress on the system and to help avoid service disruptions.”

Peak demand

California’s electricity demand had risen to as high as 44,467 megawatts on Monday and was forecast to climb even higher to 45,429 megawatts on Tuesday, California ISO said on its website at 4:50 p.m. local time. The all-time record peak of 50,270 megawatts was set in July 2006.

Spot electricity prices in Southern California surged amid the heat, and wholesale natural gas there traded at a premium of more than 22 cents per million British thermal units versus the benchmark Henry Hub on Monday, data compiled by Bloomberg show.

Natural gas-fired power generators were supplied last week with fuel needed to meet demand during the high temperatures, said Steven Greenlee, a spokesman for the grid. The state has electricity capacity reserves and no reports of major transmission line failures or generation shutdowns, he said.

Southern California Edison, a unit of Rosemead, California-based Edison International that operates the region’s biggest electric utility, said it had mobilized its emergency operation center and was deploying crews that can rapidly respond to service disruptions.

Los Angeles Mayor Eric Garcetti extended hours at several of the city’s cooling centers so residents without air conditioning could remain as late as 9 p.m. on Monday. In Palm Springs, where temperatures were expected to hit 123, special education summer school was canceled Monday, said Joan Boiko, a spokeswoman for the school district.

Officials with the California Governor’s Office of Emergency Services noted that, in 2006, about 200 people in California died from the effects of extreme heat. The office has been working with the California Department of Industrial Safety to limit the effects of the heat on workers, with the California Departing of Aging to make sure elderly people have air conditioning or access to cooling centers, and with local public health agencies, to activate local heat emergency response plans.

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