Sunday’s heat again soared above 100 degrees in more than a dozen communities, mostly east of Interstate 15. But problems also developed at and near the coast. Forecasters say overnight winds arriving from the east flowed to beach cities, causing temperatures to rise rapidly early Sunday.

The outages were scattered around the county, but hit mainly in the Rancho San Diego area, said San Diego Gas & Electric communications manager Alex Welling, who added that it was affecting about 14,000 customers service-wide, a large portion of which were in the Rancho San Diego area.

One power supplier said its systems had been overloaded by the prolonged high temperatures. Excess heat warnings remain in place for more than 17 million people in California and Arizona.