At least a dozen people, mainly firefighters, were treated for injuries that were mostly heat-related, authorities said. One person from Orange County was burned. No deaths have been reported.

The wildfires have been endangering tens of thousands of homes and other structures across the region after they sprung to life during a triple-digit heat wave over the weekend. Other major fires were burning in Idaho, Oregon and Nevada, where about 20,000 people had to flee a blaze outside Reno.

In the tight-knit community of Wrightwood that sits on the Pacific Crest Trail, authorities implored residents to evacuate the exploding Bridge Fire, which burned more than a dozen homes in the area.

Resident Erin Arias said she was racing up the mountain when she got the sudden order to leave and did, grabbing her passport and dog. On Wednesday, she and her husband doused water on the roof of their still-standing home. Their cat was missing, she said.

"It's absolutely scary," Arias said, looking at the burned embers of her neighbor's home. "We're really lucky."

UCLA climate scientist Daniel Swain said the fire moved extraordinarily fast across complex terrain, likely giving Wrightwood residents less time to evacuate than usual and surprising even seasoned fire officials.

The Bridge Fire "had to go up mountain sides, burn down slope, jump across valleys, burn across new ridges, and then make it down slope again at least two other times in effectively one burning period," he said.

California is only now heading into the teeth of the wildfire season but already has seen nearly three times as much acreage burn than during all of 2023. The White House said President Joe Biden was monitoring the wildfires in the West and urged residents to heed state and local evacuation orders.

Cooler temperatures were expected to potentially start tempering fire activity as the week progresses.