The Chrandal Creek Forest Fire is the first major fire in the Bitterroot National Forest this season.

The fire started by lightning and was detected Saturday, July 7.

The fire was about 10 acres at first, but a combination of weather factors caused the blaze to swell to over 1,300 acres.

The fire, 42 miles south of Darby, is just north of the Montana-Idaho border and has been growing in steep, rugged territory.

Helicopters dropping water were first used on the fire and now fireline construction has started on the south and west flanks of the fire. A Type 2 Incident Management team took command of the situation Thursday morning.

There are eight crews of 20 firefighters each on the lines, along with 3 helicopters and support personnel.  The Bitterroot National Forest has closed trails #184 and #106-Divide Trail, and the Mine Creek Road #5688 due to fire traffic. No structures are threatened.The Salmon-Challis National Forest in Idaho has closed the number of trails there, too.