Wildfires have cropped up in different regions across California over the past several days as a record-breaking heat wave blankets most of the state, with more fire activity expected amid a spate of dry lightning and thunderstorms.

Dangerously hot conditions hit states up and down the West Coast over the weekend, owing to a persistent heat wave stretching from the Pacific Northwest to California and the desert Southwest.

The peak of the heat wave is expected Thursday and Friday, the National Weather Service said. While it’s brought hotter temperatures than in recent weeks, it is not particularly extreme in terms of all-time Southern California highs. “This is definitely more normal heat for this time of year,” Sam Zuber, an NWS meteorologist said.