Recent rainfall in north-western Victoria has prompted concerns that hay currently being baled is too wet and could cause spontaneous combustion if not monitored appropriately, the CFA has warned.

As regional Victoria experiences spring growth of pastures and crops, CFA has issued a warning to farmers to exercise caution with the cutting, baling and storage of hay.

CFA District 18 Acting Assistant Chief Fire Officer (ACFO) Gavin Wright said he was aware that farmers were currently baling hay but warned in many areas the hay was still quite wet.

“We are urging all farmers in Victoria’s North West to take care of their hay and crops this bushfire season,” A/ACFO Wright said.

“Fodder conservation and storage is a vital and valuable component of the year-round farming operations, but it is important to ensure haystacks are prepared well and bales are stored safely.

“Keep your haystacks out of the rain to avoid fluctuating moisture content.”

A/ACFO Wright emphasised that if not monitored, haystacks pose a fire danger which could occupy crucial firefighting resources during Victoria’s bushfire season.

“When a haystack ignites, depending on the size of the stack, it can remain burning and smoulder over a long period and CFA crews are often required to monitor it for several days to make sure it doesn’t spread,” he said.

“Haystack fires can start quite easily from lightning strikes, sparks from equipment and machinery, but a major source of ignition is spontaneous combustion of the haybales themselves.”

Spontaneous combustion can occur when hay has either not properly cured before baling, or not stored to protect it from rain or damp conditions, meaning moisture content in the bales are higher than the recommended level.

This can happen to any hay bales, regardless of size. After baling, check the heat and smell of the bales before stacking them into haysheds or large external stacks, and leave any suspect bales separate from the rest.

Hot bales will often omit an odour like burning tobacco, and heat inside bales can be detected by inserting a steel rod or crowbar into the centre of a bale or stack of hay.

“If hay is stored in a shed, ensure air can circulate around the haystacks, monitor stacks on a regular basis, check for heat levels and avoid walking on stacks in case they collapse due to internal heating,” A/ACFO Wright said.

Since 2008, CFA has responded to around 1600 haystack fires. By producing hay in the right conditions and checking bales for heat before stacking haystacks, you can limit the chances of adding this seasons hay to those statistics and save yourself from loss of valuable fodder and other costly impacts of a fire.

Important Tips
  • It is important to ensure hay is well cured before bailing.
  • Know the history of the hay you purchase.
  • Keep haystacks to a limited size.
  • Monitor moisture and temperature of your hay regularly.
  • Watch for unusual odours such as pipe tobacco, caramel, burning or musty smells.
  • Store hay in separate stacks or sheds away from farm equipment and other buildings.
  • Keep your hay dry. Protect it from rain, leaking rooves or spouts, and runoff. Cover stacks with tarps or hay caps.
  • Don’t stack hay right to the top of a hay shed. Allow some air to circulate at the top - this helps to carry away moisture.
Temperature Guide – what to do when your hay is overheating
Use a thermometer in a probe or insert a crowbar into the middle of the stack for 2 hours
  • Less than 50°C (can handle bar without discomfort): Check temperature daily.
  • 50°C - 60°C (can only handle crowbar for short time): Check temperature twice daily. Remove machinery from the shed.
  • 60°C - 70°C (can touch bar only briefly): Check temperature every 2-4 hours. Move hay to improve air flow.
  • Over 70 °C (bar is too hot to hold): Potential for fire. Call 000 immediately. Avoid walking on top of haystack.
More information can be found on the CFA Hay and Fire Safety website.