Heat wave expected to drag on
Bay Area braces for Thursday scorcher, likely hottest day yet
People splash and lounge in near-100-degree heat Wednesday at Contra Loma Regional Park in Antioch. Forecasters see a dangerously hot Thursday, with temperatures expected to hit 110 in some locales. The hot spell has already proved fatal, with two deaths recorded in San Jose.
A Bay Area heat wave turned deadly this week even before temperatures were forecast to peak on Thursday in what is expected to be the hottest day of the year so far around most of the region.
At least two people have died from the heat in San Jose since the blistering temperatures began last week. Investigators in Sacramento are looking into whether three recent deaths were similarly heat-related.
Cities around the Bay Area opened cooling centers and took other precautions to prevent more tragedies as temperatures were forecast to peak in the triple digits Thursday.
Utility companies, meanwhile, are monitoring the system-wide strain and are ready to respond to temporary outages that come when tens of thousands of people run their air conditioners at the same time.
The National Weather Service issued an excessive-heat warning Wednesday morning for parts of the North Bay, inland East Bay and the entire Central Valley. The warning will last until 9 p.m. Thursday after temperatures start coming down from the expected 110-degree highs in cities like Livermore, Concord and Santa Rosa.
“These temperatures don’t occur all the time, and we think the impacts will be high,” said Brian Mejia, a National Weather Service meteorologist.
Dennis Young, 72, and Setsu Jordan, 87, both San Jose residents, died Monday of hyperthermia — a condition that happens when a body overheats, Santa Clara County Medical ExaminerCoroner’s Office officials said Wednesday.
In Sacramento, where temperatures have exceeded 100 degrees in recent days, three people were found dead outside their homes — cases that may be heat-related, county coroner’s officials said.
The South Bay deaths were not related, officials said. One of the victims died in a vehicle and the other was homeless, but officials did not elaborate on the circumstances of the deaths due to federal health privacy laws. Temperatures in San Jose hit a high of 94 degrees on Monday.
“It is tragic when someone dies of hyperthermia since in most every case it could have been prevented,” Dr. Michelle Jordan of the coroner’s office said in a statement. “Hyperthermia and heat stress happen when a body’s heatregulation system cannot handle the heat. It can happen to anyone, which is why it is so important to be in a cool location, drink plenty of water and take a cool bath or shower if you are getting too hot.”
As temperatures continue to rise, portable air conditioners have become scarce. Many hardware stores said they sold out of the units early in the week.
Peter Lee, a manager at a downtown Walnut Creek Ace Hardware, said the few air conditioners they had in stock went quick, and the extra fans they brought in are “flying off the shelves.”
Builders are still coming in to pick up lumber and drywall, but they’re also picking up several cases of water as they reluctantly head to their job sites, he said.
Dozens of cities have opened cooling centers for their more vulnerable residents. Libraries and senior centers around the East Bay and North Bay will have the cool air blasting for anyone seeking refuge from the menacing heat.
The Alameda County Health Department released a growing list of more than three dozen cooling centers and warned folks about the risks that come with unusually hot weather.
“Stay out of the noonday sun and hydrate,” said Sherri Willis, a Health Department spokeswoman. “Don’t over exert yourself and look out for elders and young children. They are the most vulnerable.”
The hot spell prompted officials at the Alameda County Fair to bump back the opening day of horse racing from Thursday to Friday.
Emergency dispatch centers have had an uptick in heat-related calls, but so far no one in Contra Costa or Alameda counties has died from the heat, officials at the coroners’ offices said.
This week’s weather sanctuary will be along the coast, where temperatures will be more than 30 degrees cooler than the worst spots around the bay, forecasters said.
Temperatures on Thursday are forecast to hit 81 in San Francisco, 97 in San Jose and San Rafael and a blistering 105 to 110 in northern Sonoma and Napa counties, Mejia said.
In locations outside the Bay Area, like the Central Valley, things might be even hotter.
Officials adjusted the schedules for dozens of races Thursday at the USA Track and Field Championships in Sacramento, where highs were forecast to hit 111.
Workers scrambling to repair the damaged spillway on the Oroville Dam have adjusted their schedules as well. They’re starting work at 5 a.m. to avoid the hottest part of the day when temperatures are forecast to hit 112 on Thursday, state water resources officials said.
Managers of California’s electricity grid are bracing for the strain on the system that will come with the spiking heat, but they doubted the extra load would lead to widespread blackouts.
Peak electricity demand was expected to hit 45,916 megawatts Wednesday and 45,822 megawatts Thursday, according to the California Independent System Operator, which manages 80 percent of the state’s power grid.
That electrical demand is well below the grid’s all-time record of 50,270 megawatts, set during the July 2006 “heat storm.”
A megawatt — or 1 million watts — is roughly the amount of electricity used by 760 typical homes at any given moment.
“We’re getting through it,” said Steven Greenlee, spokesman for the operator. “We’ve been challenged, but we’re getting through it.”
The current heat wave has not triggered any widespread outages so far, but utilities have had to deal with smallerscale blackouts, often caused by equipment overloading in the heat.
Since the heat wave began Friday, more than 236,000 Pacific Gas and Electric Co. customers have lost power, at least temporarily.
By noon Wednesday, though, only 1,000 people were without power in the Bay Area, PG&E spokeswoman Deanna Contreras said. She added that 144 of those customers lost electricity due to a broken power pole in Oakland.
The utility, which covers most of Northern and Central California, still expects to set a record for electricity demand on Thursday, even if the statewide grid doesn’t.
But even if PG&E hits its estimated peak of 22,700 megawatts, the utility said it should have more than enough electricity available.
All California utilities are required by the state to maintain a cushion in their power purchases, ensuring that they have access to 15 percent more electricity than they typically need.
Demand for power will begin to wane as temperatures start to drop after Thursday.
By the weekend, temperatures will be down more than 20 degrees in some areas as a ridge of high pressure over the region begins to dissipate.
“This is definitely going to be a significant cooldown for the weekend,” Mejia said. “It will still be hot, but we will trend toward more normal temperatures.” Evan Sernoffsky and David R. Baker are San Francisco Chronicle staff writers. Email: esernoffsky @sfchronicle.com, dbaker @sfchroinicle.com Twitter: @EvanSernoffsky, @DavidBakerSF