Multiple wildfires have already erupted in parts of the western United States, including in Oregon and California's Napa County.

In Oregon, the Flat Fire in Deschutes and Jefferson counties had grown to almost 34 square miles (88 square kilometers), with no containment, and threatened nearly 4,000 homes, according to the state Fire Marshal’s Office. About 10,000 people were under some sort of evacuation notice.

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.

Multiple small fires were reported in the Angeles National Forest on Saturday morning due to lightning strikes.