California heat wave: Flex Alert issued for 9th straight day

Scorching triple-digit heat continues to bear down on Southern California, with a ninth straight Flex Alert that will be in effect Thursday night urging residents to conserve electricity during peak hours.

Thursday's Flex Alert kicked in at 3 p.m. before expiring seven hours later.

An Excessive Heat Warning was in effect before expiring at 8 p.m. Thursday for the mountains and the Santa Clarita, San Fernando, Antelope and San Gabriel valleys, along with the inland coastal area, including downtown Los Angeles.

On Wednesday afternoon, California ISO issued an Energy Emergency Alert Level 2, urging consumers to conserve energy. The alert was in effect from 4 p.m. to 9 p.m. 

A level 3 alert was issued Tuesday night. Alerts were sent to the phones of 27 million Californians urging them to conserve energy to project the state's power grid. 

California was on the verge of ordering rolling blackouts, but the state’s electrical grid managed to handle record-breaking demand.

Demand swelled in the late afternoon and into the evening, with everyone from Gov. Gavin Newsom to the state’s legal marijuana business control agency urging people to turn off lights and reduce power or use backup generators.

RELATED: California's grid operator issues level 3 emergency

CAISO said the peak electricity demand on Tuesday hit 52,061 megawatts, far above the previous high of 50,270 megawatts set on July 24, 2006.

"A prolonged period of very hot conditions with minimal coastal clouds is expected as high pressure aloft remains anchored over the West," according to the National Weather Service. "Triple-digit heat will be common for many valley and mountain locations through early next week. Record-breaking heat will produce a very high risk of heat illness."

"Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors," the NWS urged. "Young children and pets should never be left unattended in vehicles under any circumstances."

Forecasters also urged residents to be aware of the signs of heat stroke and to take precautions.

"Take extra precautions if you work or spend time outside," NWS forecasters said. "When possible reschedule strenuous activities to early morning or evening. Know the signs and symptoms of heat exhaustion and heat stroke.

"Wear lightweight and loose fitting clothing when possible. To reduce risk during outdoor work, the Occupational Safety and Health Administration recommends scheduling frequent rest breaks in shaded or air conditioned environments. Anyone overcome by heat should be moved to a cool and shaded location."

The California Independent System Operator -- which manages the state's power grid -- issued the statewide Flex Alert from 4 to 9 p.m. Wednesday. Residents are urged to take the following power-saving steps:

-- setting thermostats to 78 degrees or higher;

-- avoiding use of major appliances;

-- turning off unnecessary lights; and

-- avoid charging electric vehicles.

Residents are also advised to pre-cool their homes as much as possible and close blinds and drapes to keep interiors cool.

The alerts have worked thus far, with the state avoiding involuntary power cutoffs. Officials said Sunday, Monday and Tuesday in particular are shaping up to be the most difficult days of the heat wave. Tuesday's peak demand is forecast to be 50,087 megawatts, just shy of the all-time record of 50,270 set in 2006.

According to Cal-ISO, electrical demand on Sunday was estimated at about 45,000.

The five year-round pools operated by the Los Angeles County Department of Parks and Recreation, which are usually closed on Labor Day, will be open Monday because of the heat, the department's Director Edith García- Gonzalez told City News Service.

Cooling centers for Los Angeles County can be found at Cooling centers for the city of Los Angeles can be found at, or by calling 311.

The Associated Press contributed to this report.