Bizarre weather sends hay bales up in flames

By Asa Wahlquist

January 21, 2008 12:00pm

THE recent unusual weather patterns have accelerated one of the strangest phenomena witnessed in the bush: an unprecedented number of haysheds have been spontaneously bursting into flames.

Throughout the grain belt, it has been the worst season ever for spontaneous hayshed fires, according to the executive officer of the Australian Fodder Industry Association, Colin Peace.

He estimates there have been 400 incidents of spontaneous combustion of haysheds in NSW alone.

From northern NSW to South Australia, haystacks and haysheds have been bursting into flames.

Drought, followed by summer rains, microbial growth in the stack and then hot, dry conditions can result in the spontaneous combustion of hay.

"The combination of flammable material, moisture and bacteria - you get those three things together, they generate heat and it spontaneously combusts," Mr Peace said.

Most of the fires are occurring in wheat and barley too poor to reap because of the drought. Instead, farmers baled them for hay.

One theory is the wheat and barley have a higher level of sugar than the usual oaten hay, leading to increased microbial activity.

Another view is that the hay has not been properly dried or cured. Hay is routinely checked with a moisture probe.

Large bales must have a moisture content of less than 14 to 18 per cent. A moisture content of more than 18 to 22 per cent puts them at risk.

The heavy summer rain has penetrated haysheds, and soaked into bales.

"Paddock-stacked bales have become wet and they are spontaneously combusting," Mr Peace said. "You have even had individual bales in paddocks going up in smoke."

Gordon Hill, regional operations manager for the west region of the NSW Rural Fire Service, said: "In our region since late October, we have had 84 fires. It is unusually high. In an average year, we'd be flat out getting any more than five or six.