Photo: Contributed - R. Leyenhorst

A hay barn erupted in flames in Armstrong, Wednesday evening.

The fire started about 6:30 p.m. on Knob Hill Road, near the Hulcar Hall, according to neighbours.

There is no word on the cause of the fire or any injuries. However, wet or recently harvested hay can spontaneously combust due to microbial growth, causing changes in heat and oxygen availability within the hay pile, according to Washington State University.

The blaze produced a thick pall of smoke that drifted across the valley.

It is said to have sparked at the Jansen family farm.