CFA’s community safety manager James Haley said that even though western Victoria had experienced significant rainfall over spring, it might still not have been enough to extinguish tree stumps and large rubbish piles that had been burnt off. 

A grass fire near Penshurst on Wednesday that burnt a small area adjacent to the Hamilton Highway was believed to have started from a burn off up to six weeks ago. 

Mr Haley said the fires might smoulder in underground root systems for a number of months, which could flare up when the ground and vegetation dried out and the warmer summer winds fanned the hot spots.

Landholders should also regularly monitor all haystacks for signs the hay was heating, because the wet spring made it difficult for farmers to roll or bale it at the lower moisture level required, he said.

“This check can be done using a crow-bar or temperature probe, although this will not detect heat deeper into the stack,” Mr Haley said.

“Other signs of heating include steam rising from the stack, condensation or corrosion under the hayshed roofing, mould growth in or on the bales, unusual odours such as burning, musty, pipe tobacco or caramel, or slumping in sections of the haystack.”

Spontaneous combustion of haystacks generally occurs between two to 18 weeks after baling, with the average being 11 weeks.

Mr Haley said if there were signs the previous burn off or hay was starting to heat up, it was important to have the local CFA fire brigade in attendance in case the burn off reignited while attempting to cool the roots, or as the hay stack was pulled apart to improve airflow around the bales. 

He reminded landholders that on days when a Total Fire Ban was declared, activities such as welding, grinding and using an incinerator were not permitted. 

Activities with a fire risk such as using chainsaws, slashers and harvesting equipment should also be postponed.