(Bloomberg) -- California’s grid operator said the state successfully avoided rolling blackouts Tuesday during a brutal heat wave -- but some cities apparently didn’t get the message.

Officials in four Northern California cities -- Alameda, Healdsburg, Lodi and Palo Alto -- reported on social media that power shutdowns were underway Tuesday evening, after the state’s grid operator declared the highest level of energy emergency and heat pushed electricity demand to a record high.

But the California Independent System Operator said it hadn’t ordered blackouts. Instead, it only issued an alert telling utilities to line up customers for a power cut should one prove necessary, spokeswoman Anne Gonzales said Wednesday. The four cities, whose utilities all belong to the same joint powers agency, jumped immediately to cutting electricity, she said.

“It was a miscommunication somewhere, and we regret it,” Gonzales said. “It’s never our intention to have people without power. We’re tightening up those communications procedures.”

The incident raised questions about the effectiveness of the state’s communications with utilities, local officials and residents during grid emergencies, when California increasingly relies on conservation to avert blackouts in a pinch.

Read: A Text Alert May Have Saved California From Power Blackouts

California has come to depend on public conservation to avoid outages during such circumstances. Homes and businesses slashed electricity use Tuesday evening after the state Office of Emergency Services blasted out a mobile alert begging for more conservation.

(Adds city of Lodi to paragraph two, explanation for incident in paragraph three and quote from grid operator in paragraph four.)

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Author: David R. Baker