As a massive heatwave spreads across California and the Western U.S., officials are warning of both rolling blackouts and increased wildfire activity. Temperatures as much as 20°F above normal are expected to remain through the weekend and the California electrical grid operator (CAISO) to reduce their electricity consumption to ease strain on the grid as air conditioning drives up demand. CAISO also said customers should “avoid charging electric vehicles” during periods of high strain on the grid.

Gov. Newsom also declared a state of emergency, which will allow the use of backup diesel generators and pauses requirements that ships plug into ports’ electricity. While the measures will help keep the lights on, they will also increase air pollution, the danger of which is compounded by extreme heat.

Wildfires on Wednesday already forced evacuations across the state and officials worry and expect the heat will fuel increased fire activity. Not only does the heat dry out vegetation, it also increases the strain on firefighters doing physically demanding work while carrying heavy gear. House GOP Whip Steve Scalise criticized CAISO’s statement about EV charging, which comes a week after CARB declared all new cars sold in California by 2035 must be EVs. (Heat & Grid: LA Times $, Washington Post $, Sacramento Bee $, AP, CNN, San Francisco Chronicle, NPR, Bloomberg $, Reuters, New York Times $, Yahoo; State of Emergency: AP; Health risks: The Guardian; Fires: AP, Sacramento Bee $, KCRA Sacramento; EV charging: USA Today, ABC-10, Washington Examiner, Fox News; Climate Signals background: Extreme heat and heatwaves, Wildfires)