A Text Alert May Have Saved California From Power Blackouts

(Bloomberg) -- A timely mobile alert may have prevented hundreds of thousands of Californians from being plunged into darkness in the middle of a heat wave Tuesday night.

Just before 5:30 p.m. local time, California’s grid operator ordered its highest level of emergency, warning that blackouts were imminent. Then, at 5:48 p.m., the state’s Office of Emergency Services sent out a text alert to people in targeted counties, asking them to conserve power if they could.

Within five minutes the grid emergency was all but over.

Power demand plunged by 1.2 gigawatts between 5:50 and 5:55 p.m., and would continue to drop in the hours after that, according to data from the California Independent System Operator. A gigawatt is enough to power about 750,000 Californian homes.

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But while the state’s grid operator said California had avoided rolling blackouts Tuesday, some cities apparently didn’t get the message. Officials in three San Francisco Bay area cities -- Alameda, Healdsburg and Palo Alto -- reported on social media that power shutdowns were underway that evening, which also could have contributed to the sharp decline in demand.

Read: Muddled Messages of California Blackouts Spark Confusion

By 8 p.m., the grid operator canceled the highest level of emergency without calling for power cuts. More than 500,000 homes and businesses had been warned earlier in the day that they might lose service.

Temperatures set records across the state Tuesday, with Sacramento reaching 116 degrees Fahrenheit (47 Celsius), an all-time high in records going back to 1849. The heat is expected to persist for the next few days before easing by the weekend. In Southern California, Burbank and Riverside may both reach 109 degrees Fahrenheit Wednesday.  

(Updates with municipal confusion in fifth paragraph)

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