A week-old wildfire in southern California picked up steam late on Thursday and early Friday as firefighters in the drought-stricken state struggled to find enough water to contain the blaze.

The fire has so far consumed about 40 square miles of the San Bernardino mountains, about 90 miles east of Los Angeles. It is one of several fires spreading along the west coast this week, and one of 2,500 fires to break out this year alone in California.

The wildfires have been exacerbated by the historic drought in western states. Almost 70% of California is considered to be in “extreme to exceptional drought”, according to the National Drought Mitigation Center.

“Normally at this time of year, we’d be seeing green and wildflowers as far as we can see,” Orange County fire captain Dave Lopez told CBS News. “But because of the drought, we’re seeing brown, dry fuel that has no moisture in it at all.”

The drought is also making it harder for authorities to find bodies of water, meaning planes and helicopters are flying farther and farther away to reload. Personal drones being used to film the fire have also gotten in the way of planes filled with retardant.

“I think this is going to be the worst fire season we’ve seen yet,” Lopez told CBS. “And next year will probably be worse than that unless this drought breaks.”

Residents in the tiny towns of Burns Canyon and Rimrock have been told to evacuate. The fire department says as many as 7,390 structures are threatened by the fire.

Wildfires have also been spreading in remote parts of northern California, Oregon, Washington and Alaska. While most of the fires are small, Alaska is grappling with about 300 of them. The state’s snow cover melted off much earlier than usual this year thanks to an exceptionally hot May, giving the fires more opportunity to spread. Those fires are also threatening the state’s permafrost – underground frozen soil – which if burned could release massive doses of carbon into the atmosphere.