Flex Alert Issued As 'Dangerous' Heat Wave Hits Southern California

LOS ANGELES, CA — Forecasters are anticipating the most "dangerous" heat wave of the year to bear down on Southern California through Tuesday. As temperatures rise, officials are warning residents to be aware potential of power outages and heat-related illnesses.

The California Independent System Operator issued a Flex Alert Wednesday afternoon, asking residents to reduce power usage to ease stress on the power grid as temperatures rise 10-18 degrees warmer than normal through the week from across all Southland counties, grid operators announced Tuesday. The Flex Alert goes into effect at 4 p.m. Wednesday and lasts through 9 p.m.

"Restricted Maintenance Operations" have been issued through Tuesday from noon to 10 p.m. each day, Cal ISO said. If weather or grid conditions worsen, grid operators said they may issue a series of emergency notifications to access additional resources.

“When we hit these heat waves, we’re seeing more load on the system,” Severin Borenstein, a professor at Haas School of Business at UC Berkeley, and the faculty director of the Energy Institute at Haas, told KCRA. “We really are going to have a tight weekend due to the extreme heat and do need people to be cognizant of that.”

Over the long weekend, Californians will be asked to further reduce power usage from 4 to 9 p.m., when the grid is most stressed amid demand for electricity.

Residents are asked to make the following adjustments this weekend:

• Set thermostats to 78 degrees or higher
• Avoid using large appliances
• Avoid charging electric vehicles
• Turn off unnecessary lights

"Lowering electricity use during that time will ease strain on the system, and prevent more drastic measures, including rotating power outages," grid operators wrote in a statement.

Pacific Gas & Electric Co. is also asking customers to heed energy reduction requests issued by the grid operator.

“To reduce strain on the grid, we recommend that customers use their major appliances – washer, dryer dishwasher, oven and stove — use those earlier in the day because it's hot in the late afternoon,” Megan McFarland, a PG&E spokesperson told KCRA.

The National Weather Service has issued an excessive heat warning from San Diego to Sacramento and has cautioned about the health risks associated with elevated temperatures.

An excessive heat warning remains in effect from 11 a.m. Wednesday morning to 8 p.m. Monday with temperatures expected to climb from 85 to 100 degrees through Thursday and 90 to 105 degrees Sunday and Monday. At night, forecasters anticipate abnormally warm overnight lows between 65 and 75 in Santa Barbara County South Coast, Ventura County Inland Coast, and Los Angeles County Inland Coast including Downtown Los Angeles.

In Riverside County, temperatures rose a few degrees Monday and were spiking even more Tuesday -- with more of the same in the forecast for Wednesday and beyond.

"The abnormally long-duration heat wave remains on target. Excessive heat warnings will go into effect on Wednesday for all areas inland of the beaches, and last through Monday," the National Weather Service said.

An excessive heat warning has been issued until 8 p.m. Monday with dangerously hot conditions in the forecast and temperatures expected to reach between 105 and 112.

In San Diego County, An excessive heat warning is in effect from 10 a.m. Tuesday through 8 p.m. Monday in the county, including the city of Santee, according to the National Weather Service.

Over the period, "dangerously hot conditions"are expected with temperatures well into the 80s at the beaches, the 90s in the inland valleys and up to 115 in the deserts. High humidity levels will make it feel even hotter, according to the NWS.

Forecasters urge the public to take these precautions beginning Thursday:

• Avoid being outdoors during the day;
• Stay hydrated and in a cool place;
• Use air conditioning if available; and
• Cancel outdoor activities during the hottest period of the day.

"Dangerous heat is expected later this week through the Labor Day Weekend. There's an increasing risk for heat-related illness with a high HeatRisk. Plan ahead for adequate cooling and hydration especially if you have outdoor plans," weather service officials tweeted on Wednesday.

Although grid operators are urging residents to reduce energy usage, weather service officials warn that in many areas, fans will not be adequate to keep cool.

"The combination of hot daytime temps and warm overnight lows over several days will lead to very high risk of heat-related illness for all populations," NWS officials said. "Fans will not provide adequate cooling, so use Air Conditioning or seek A/C at a public location or local cooling shelter."

Weather officials expect this heat wave to be "exceptionally dangerous" due to extreme afternoon highs and "oppressive" overnight lows.

Residents are urged to keep tabs on vulnerable family members, neighbors and friends. Newborns, pregnant people, children, elderly residents and those with chronic illnesses are especially at risk, officials said.

"Everyone is at risk from the dangers of extreme heat, but these groups are more vulnerable than most," NWS officials said. "Age and certain conditions make the body less able to regulate temperature."

Residents are also urged to protect their pets.

The Kennel Club has advised that dogs should not be walked on pavement during extreme heat because it can burn their paws.

The best way to tell if a pavement is too hot for your dog to walk on is to place the back of your hand on the pavement for seven seconds. If it’s too painful for your hand, then it’s too painful for your dog’s paws, the Kennel Club said.

The Society for the Prevention of Cruelty to Animals has reminded residents to never leave pets inside a locked vehicle, even for short periods of time, since the interior of a vehicle parked in the heat can quickly turn deadly.

Bay City News and City News Service contributed to this report.