A historic heat wave continued to torch the Bay Area and state with temperatures surging back to triple-digits in some inland areas.

The California Independent System Operator, which manages electricity over the state's high-voltage transmission lines, has called for a series of Flex Alerts in the past week to encourage people to reduce their energy use.

Thursday's alert went effect from 3 to 10 p.m., and it expired as Californians avoided rolling blackouts once again.

We are grateful to Californians and our many partners across the West who continue to help the #ISO work through this very challenging week. Thank you! Reminder: A #FlexAlert is in effect tomorrow, Friday, Sept. 9, from 4-9 p.m.

CAISO has also issued an Energy Emergency Alert 2 from 4 to 9 p.m. The second of three emergency alert stages means taking emergency energy-saving measures. Stage 3 would be rolling blackouts.

#ISO has issued an Energy Emergency Alert (EEA) 2 effective today, from 4 p.m. – 9 p.m. When an EEA 2 is called, @California_ISO requests emergency energy from all resources and may activate its demand response program. https://t.co/oR4B23tvzO pic.twitter.com/kPnRYoJvwl

The grid operator encourages people to take steps like setting their home or business thermostats to 78 degrees or higher during Flex Alerts, as well as to avoid the use of major appliances and to turn off any unnecessary lights.

PG&E this week also warned hundreds of thousands of customers across the state to prepare for possible outages when the grid could not reach its minimum reserves.

The ISO extended the time for today’s #FlexAlert to 3-10 p.m. because there are projected market deficiencies during that time. pic.twitter.com/bZqqim6A5c

On Tuesday, the state saw an all-time record high peak demand on the power grid, reaching 52,061 megawatts, but narrowly avoided having to institute widespread rotating power outages because of conservation efforts by residents.

The heat wave is expected to linger Friday, but temperatures in the Bay Area are expected to drop into the upper 90s to 105 degrees inland. The region is expected to cool down by the weekend to more normal seasonal temperatures, according to the weather service.

Visit the NBC Bay Area weather page to get your microclimate forecast.

Bay City News contributed to this story.

Bay City News contributed to the report.