BOISE, Idaho (AP) — Residents in west-central Idaho near the town of Riggins have been told to flee due to a wildfire that expanded to 40 square miles Thursday, an 11-square-mile jump.

Fire managers say the fire made runs through the tops of trees and had long-range spotting with embers shooting out ahead. Nearly 600 firefighters are working to protect structures, put in fire lines and use burnouts along U.S.

Highway 95 and the Salmon River. Officials say they expect the fire to make runs to the north and east, and that the fire is also actively burning south after crossing a creek. There are 21 large fires burning in Idaho, the National Interagency Fire Center says.