Bigfork resident Les Potts was driving south on Montana Highway 35 just north of McCaffery Road on Friday morning when he suddenly noticed something abnormal behind him — the straw in the 30-foot trailer he was pulling had caught fire.

Potts managed to pull over and instinctively went to unhook the trailer from his 1993 Dodge truck before the flames leapt to the vehicle while a passerby called in to report the fire.

“Ask me how it started? I don’t know,” Potts said.

Firefighters from both Creston and Bigfork were called to the incident just before 11 a.m. They used foam to control the flames. Five fire trucks and a water tender were at the scene.

Operator Terry Sullivan with Flathead County was called to unlock the gate to the county pit across the highway from where the straw was burning on the west edge. Crews then worked to move the burning bales to the property to extinguish the fire further away from nearby farmland.

To Sullivan, watching firefighters put out the straw was of particular interest, because his fields were the ones separated from the fire by a fence and only a few yards of ground cover.

Traffic in both directions was blocked for several hours.

The cause of the fire is unknown.