RUIDOSO, NEW MEXICO — A wildfire ignited by the fatal crash of a small medical plane outside Ruidoso, New Mexico, has forced evacuations in a rural area north of the Capitan Mountains and prompted closures in the Lincoln National Forest, officials said. The blaze nearly doubled in size between Sunday and Monday morning, growing to more than 19 square miles (50 square kilometers).

The plane went down before dawn Thursday outside Ruidoso while en route from Roswell Air Center to Sierra Blanca Regional Airport. All four people aboard were killed: pilots Keelan Clark and Ali Kawsara with Generation Jets, and flight nurses Jamie Novick and Sarah Clark with Trans Aero MedEvac. The Federal Aviation Administration and the National Transportation Safety Board are investigating the crash.

More than 600 firefighters from the U.S. Forest Service, the Bureau of Land Management and several interagency Hotshot crews worked to fight the wildfire. Steep, rugged terrain has made it impossible for crews to engage the fire directly, Adam Turner said. Turner said crews were working to contain and steer the fire away from several evacuated cattle ranches to the northeast and the community of Arabella to the west.

A red flag warning remained in effect across southern New Mexico on Monday, with wind speeds forecast between 20 and 30 mph (32 and 50 kph). The forecast conditions added to the challenge facing the more than 600 firefighters battling difficult terrain as they worked to protect the evacuated ranches and nearby communities.