Most of the 5,000 acres of growth of the Moose Fire in eastern Idaho Friday was on the west and east sides, spreading for about a mile to the east and west. The fire burned actively Friday night, spreading west as far as Kayak Camp. In the North Fork area it reached the west bank of the Salmon River. Two miles of the east flank are on the steep slopes west of and above U.S. Highway 93.

Friday’s Red Flag weather conditions increased fire activity along the top of Napoleon Ridge. North of the Salmon River, firefighters succeeded in holding fire line built during the last several days.

It was mapped at 28,839 acres late Friday night and was 12 miles northwest of Salmon, Idaho, and 10 miles west of the Idaho-Montana border.

Two pilots were killed Thursday when their Chinook helicopter crashed into the Salmon River while working on the fire. They were identified as Thomas Hayes, 41, of Post Falls, Idaho, and Jared Bird, 36, of Anchorage, Alaska. The National Transportation Safety Board will conduct an investigation.

A representative for the Salmon Challis National Forest said the cause of the fire is undetermined.