FORT COLLINS, Colo. (AP) — Firefighters are trying to stop a new wildfire in northern Colorado.

The U.S. Forest Service says the Seaman Fire about 18 miles (29 kilometers) northwest of Fort Collins was discovered Tuesday afternoon and wind caused the fire to spread to between 100 to 200 acres (40 to 81 hectares) by Wednesday morning.

The fire near Seaman Reservoir is believed to have been sparked by lightning and is burning mostly on the Roosevelt National Forest. The Forest Service says the nearest structures are a half-mile (0.8 kilometers) away and the small community of Poudre (POO'-dur) Park along the Poudre (POO'-dur) River is 1.5 miles (2.4 kilometers) away.

There are several older fires smoldering in western Colorado and a red flag warning was in effect there Wednesday.