LOS ANGELES (AP) — Californians were urged to conserve electricity again Wednesday as the searing heat wave roasting the West strained the state’s electrical grid and raised the threat that another round of rolling blackouts might be needed to reduce the load on the system.

Grid operators moved up the start of the so-called Flex Alert by an hour to 2 p.m. based on experience with demand and conservation over previous days in which use of blackouts was narrowly avoided. The alert was expected to end at 9 p.m.

“Tonight we believe … is the last night we really need everybody to do everything in their power to flex their power use, power consumption,” Gov. Gavin Newsom said.

The state has been in the grip of an oppressive, humid weather system for days, sending temperatures into triple digits in many areas.

“Some have described this high pressure as a heat dome that has impacted not just the state of California but the entire West Coast of the United States,” Newsom said.

The California Independent System Operator, the nonprofit organization that oversees the state power grid, ordered utilities to cut power to selected areas Friday and Saturday nights.

The Democratic governor, who has ordered an investigation into why those blackouts had to be instituted, credited residents, industries and businesses for responding to the crisis.

“Monday and Tuesday of this week the conservation efforts are the reason and probably the only reason we were able to get through those days without any kind of load disruptions,” Cal ISO President Steve Berberich told a conference call.

While there was continuing competition for resources throughout the West, the outlook for importing energy into California improved Wednesday, there was more wind power and there were no more cloud cover issues for solar production, he said.

“Right now, absent loss of any big (generating) units or transmission lines, we do not expect any load disruptions,” Berberich said, but added that “we’re counting on those conservation measures to be able to say that.”

The wildfires raging in many parts of California had so far not affected transmission lines, he said.

“We are quite mindful that people are fatigued. We believe if we can get through today, the load numbers start to come down as the week goes on and then we get into the weekend,” Berberich said.

The load predicted for the start of next week appeared high, but the forecast and resources would be clearer closer to that time, he said.