Rain during hay-making season and a big increase in hay being harvested has seen a number of hay shed or stack fires breakout this summer season.
At last count more than 30 fires in hay supplies have been reported since November, 2018 in northern Victoria. Other regions have also reported fires.
Many parts of Victoria received unseasonal rains during the harvest period and that had impacted hay making operations leading to some hay being baled when moisture levels were too high.
After a dry growing season there was also a large increase in the amount of hay cut from failed cereal crops.
CFA has reported that many of the fires were the result of self ignition due to excessive heat build-up.
CFA Community Engagement Co-ordinator for Region 18 and 20, Kevin Sleep, Swan Hill, said that across the Mallee region there had been 16 hay stack fires so far.
There were also a number around the Wimmera as well as parts of the Northern Country – or 30 to 35 hay stack fires in the North West.
He said that on average CFA data showed there were an average of 150 hay stack fires across the state each year.
There had been a gradual increase in fires with the increase in the export hay market particularly in the north of the state, he said.
The poor season also saw many crops in the northern part of the state not reaching a level to take through to a grain harvest cut for hay instead to regain some revenue.
Mr Sleep said some issues were stacks not being covered with tarpaulins or bale caps as well as the increased use of large rectangular bales.
He said round bales with nylon wrapping tended to shed the water, not allowing it to soak in.
The past two summers there had been summer rainfalls and hay stack fires as a result.
CFA District 20 Operations Manager, Peter Taylor, said that in the last few weeks, brigades across the Mallee and Wimmera had been called out to a number of Haystack fires including four days when there were four hay fires across the area.
“The main cause of the fires appears to be spontaneous combustion which is caused by bacteria that grows within green or damp hay and produces a chemical reaction that causes hay to heat,” Mr Taylor said.
Signs of heating hay
- Steam rising from haystacks
- Condensation or corrosion under hay shed roofing
- Mould growth in or on bales
- Unusual odours (burning, musty, pipe tobacco or caramel)
- Slumping in sections of haystack.
According to Agriculture Victoria large rectangular bales, due to their high density that restricted heat dissipation, were the most prone to heating and spontaneous combustion.
Large round bales due to their large volume and dense nature, although less dense than the large rectangular bales, were the next prone. Small rectangular bales are the least vulnerable.
However, heating and spontaneous combustion could occur in all bale types in the right conditions.
Agriculture Victoria says environmental factors such as relative humidity (RH), ambient temperature and air movement could interact and compound the issue of hay heating.
At any temperature hay needed much longer to dry at higher RH than at a lower RH.
Air flow over a stack aids in the removal of evaporated moisture and dissipated heat which reduces the build-up of heat and relative humidity around the stack.
Tips for preventing hay fires or unnecessary losses:
- Allow for airflow by not stacking hay right up against the roof of sheds.
- Store hay in multiple locations or stacks to avoid large losses if a fire occurs.
- Cover your hay with hay caps or a tarpaulin.
- Never carry out work such as welding or grinding near haystacks.
- Maintain a break around stacks.
- Monitor stacks regularly and separate if overheating
- Don’t walk across the top of severely heated stacks as they could collapse inwards and cause serious injury.
Mr Sleep said that at this stage of the season, the main thing for farmers was to monitor stacks for steam, slumped areas, a molasses or caramel smell.
He said farmers could also check bale temperatures with a probe.
Stacks needed to be kept under observation to note changes and whether action needed to be taken.
Farmers should put a break around stacks to reduce the chance of a fire spreading.
Mr Sleep said hay fires used resources that may need to attend grass or scrub fires.
During the recent extreme temperatures the CFA had introduced a “hot day response” which meant a minimum of five tankers deployed to fires as they were reported.
