 Bloomberg -- California is bracing for another round of targeted blackouts Monday as a heat wave continues to smother the region and power supplies run low.The states grid operator informed PGE Corp. late Sunday that no rolling outages would be needed for the rest of the weekend, according to the utility. The respite, coming after two consecutive nights of blackouts, may be fleeting. The California Independent System Operator has warned it may not have adequate supplies over the next few days to meet the anticipated crush of demand for electricity to power air conditioners and fans.Since Friday, millions of people statewide have been briefly plunged into darkness as the California ISO has called for shut-offs to cope with surging demand for the first time since the 2001 energy crisis. It comes during one of the worst heat waves to hit the state in generations.The worst may be yet to come. The heat isnt forecast to peak until Tuesday or Wednesday. By then, the states aging power equipment may be pushed to the brink. Transformers -- the metal cylinders sitting atop power poles -- can malfunction and even catch fire if they cant cool off at night. During a 10-day heatwave in 2006, California utilities lost more than 1,500 of the devices, with each knocking out one neighborhood in the process.Monday and Tuesday will be quite hot, and there will be a number of records again, said David Roth, a senior branch forecaster with the U.S. Weather Prediction Center. It is pretty much the whole West.The heat and the blackouts come nearly a year after California utilities intentionally cut power to millions in an effort to prevent live wires from sparking wildfires during windstorms. This round of outages come at an especially vulnerable time, with Covid-19 forcing people to remain at home. Thats left those without power with a difficult choice between enduring the heat indoors and seeking relief elsewhere.The heat wave gripping the West Coast stems from a stubborn high-pressure system that has centered across the Great Basin that spans Nevada and other western states. It essentially acts as a lid trapping hot air, and there arent any indications its going to budge soon.Such phenomenons, sometimes called heat domes, are getting worse as the Earths climate changes. As the planet warms, the contrast between the heat at the equator and the cold at the pole decreases. That saps the strength of the jet stream, which otherwise would be able to shove the ridges out of the way. Hence, heat waves get stuck in place for longer.Extreme weather has taken a profound toll on electrical grids in recent weeks. Last week, millions of people lost power across the U.S. Midwest after a wall of lightning, hail and deadly winds tore a path of ruin from central Iowa to Chicago. Days earlier, Tropical Storm Isaias darkened homes from the Carolinas to Connecticut.Read More: Blame Climate Change for Heatwave Misery: Green InsightCalifornias outages began Friday, when a power plant malfunctioned just as demand peaked. Grid operators ordered utilities to cut back, and about 2 million people lost service over the course of four hours. A similar episode played out Saturday, when an estimated 352,500 homes and businesses briefly went dark.Im pretty shocked by this -- I think everybody is, said Michael Wara, director of the Climate and Energy Policy Program at Stanford University. This has to be addressed with a lot of attention, and fast.Before Friday, Californias grid operator hadnt imposed rolling blackouts since the energy crisis of 2001, when hundreds of thousands of customers took turns being plunged into darkness, power prices surged to record levels and the states largest electric utility went bankrupt. It went bankrupt a second time last year in the face of crippling wildfire liabilities.Read More: One Million Lost Power in Storm That Spawned Chicago TornadoMandy Feuerbacher, an immigration attorney in Los Gatos, saw her lights go out without warning on Friday evening. Her two-year-old twins were up until 2 a.m. crying from the heat. She and her husband moved their beds into the downstairs kitchen, hoping it would be cool enough in there for them to sleep.The babies were so hot. They were freaking out. We were really worried about our food spoiling, Feuerbacher said. It was terrible.For more articles like this, please visit us at bloomberg.comSubscribe now to stay ahead with the most trusted business news source.2020 Bloomberg L.P. 