Two lightning-sparked fires burning in remote Northern California forests prompted evacuation warnings and strained firefighting resources already stretched thin by an unusually early and active burning season.

The Monument and McFarland fires were two of at least nine ignited in the Shasta-Trinity National Forest as thunderstorms rolled through Thursday to Saturday.

The Trinity County Sheriff’s Office issued evacuation warnings for the communities of Big Bar and Del Loma on both sides of the Trinity River about 10 p.m. Saturday as the Monument fire grew rapidly, threatening about 22 homes. By Sunday afternoon, the McFarland fire had spurred an evacuation order for residents of the town of Wildwood, which includes about 60 homes.

The fires were burning amid historically dry conditions and a series of heat waves linked to human-caused climate change. It was the area’s third-warmest July on record, with the average high in Ukiah over 100 degrees, according to the National Weather Service. Temperatures there remained about 5 degrees above normal Sunday.