Frost raises fire danger, Otago farmers warned

A hoar frost in Omakau last month. Photo / Alexia Johnston

Frost dries out vegetation and farmers need to stay vigilant when burning off during winter.

That is the warning from Otago principal rural fire officer Graeme Still, who said the large blaze near Hindon on Tuesday evening and several fires in shelter belts since Friday were worsened by recent frosts.

''What happens is the frost sucks the moisture out of fuels, especially fine fuels, such as grasses,'' he explained.

''And without rain, which we haven't had a lot of, people can get caught out when they light their fires, because all the surroundings are quite dry.''

The risk was increased by the current surplus of feed, which in some places had not been eaten off and was beginning to die.

''The growth has started to die off and coupled with the frosts, it's causing a few problems.''

The recent lack of rain had also ramped up the fire danger in Otago, he said.

Still urged farmers to be aware frosts ''cure'' fine fuels and to take care when burning off this winter.

''You just need to be vigilant.

''Even though we're into the winter period, we're still getting the days where the fine fuels have dried out because for the frosts.

''Make sure you've got plenty of space around your burn, or you've got measures in place to insure [the fire] doesn't escape among those fine fuels.''