ISLE ROYALE, Mich. (AP) — A wildfire on Michigan’s remote Isle Royale has been about 15% percent contained and crews have saved some historic cabins from encroaching flames, an official said Wednesday.

The fire began Aug. 10, apparently sparked by a lightning strike on the drought-stricken wilderness island, said Liz Valencia, a spokeswoman for Isle Royale National Park.

“It’s extremely dry on the island, so it probably didn’t take much,” she said Wednesday.

The wildfire on the 571,000-acre (231,075-hectare) Lake Superior island has left a little over 200 acres either scorched or still burning, Valencia said. Crews are not actively fighting the fire, but they are monitoring the flames to make sure they don’t threaten any park infrastructure, she said.

“It’s moving very slow right now,” Valencia said.

The National Park Service closed some trails and campground areas after gusty weekend winds quickly increased the size of the fire, which is burning on the northeastern end of the island.

The fire’s rapid spread prompted fire crews on Monday to use special planes to collect water from Lake Superior to douse flames and protect some historic cabins dating to the early 1900s on small islands within the park’s Tobin Harbor. But flames did destroy one outhouse, Valencia said.