■ PG&E proactively cuts power to 1,600 customers due to red flag weather.

Move designed to prevent wildfires affects 1,600 customers

SAN FRANCISCO — Pacific Gas & Electric cut power to selected portions of Northern California on Saturday to guard against wildfires as the weather turned very windy, dry and hot.

Electricity was turned off around 6 a.m. to 1,600 customers in parts Napa, Solano and Yolo counties. Just as that shutdown was called off, the utility warned 27,000 customers in Butte, Yuba, Nevada, El Dorado and Placer counties that their power would be cut from 9 p.m. through Sunday morning.

The end of the earlier shutdown was announced around 4 p.m., and the utility said power would be restored in those areas as soon as crews finished checking lines for any weather-related damage.

Conditions ripe for fire — winds, low humidity, dry vegetation and heat — were expected to last into Sunday. The National Weather Service office reported a 71 mph gust on one peak in the region.

A fire that erupted late in the day in Yolo County was estimated at 100 acres; firefighters halted the spread of another after 25 acres burned northeast of Calistoga in Napa County. The causes were not immediately known.

PG&E is under pressure to prevent fire starts after downed power lines and other company equipment have been blamed for conflagrations that began during so-called fire weather.

But there has been opposition from customers who rely on electrically powered life-support equipment as well as businesses that have had to shut down for lack of power.

“We know how much our customers rely on electric service, and our decision tonight to turn off power is to protect our communities experiencing extreme fire danger,” Michael Lewis, PG&E’s senior vice president of electric operations, said in a statement Friday.

California experienced a very wet winter and spring, and even vast areas that were scorched earth after last year’s wildfires now have new head-high brush that is rapidly browning as summer approaches.

Two fires broke out heading into the weekend.

A grass fire Friday afternoon near the Solano County community of Fairfield forced people out of about 50 homes. But firefighters held it to 24 acres without any structures lost and evacuations were lifted.

A wildfire near Interstate 5 in Stanislaus County grew to nearly 1 square mile. But it was 75 percent contained Saturday, according to the California Department of Forestry and Fire Protection.

The California Public Utilities Commission has said power providers must do a better job of educating and notifying the public and increase fire prevention efforts such as clearing brush and installing fire-resistant poles.