Waitaki is split into two fire zones: Coastal Waitaki is in a restricted fire season, meaning burns are allowed only by permit; and Upper Waitaki is in a prohibited fire season, meaning no fires are allowed at all.
On Monday MetService put out a warning for severe thunderstorms around Oamaru.
The storm that hit was fierce, with heavy rain and strong thunder, but over within a few hours.
Fire and Emergency New Zealand assistant area commander Mike Harrison said the rainfall was "not going to make any difference to the fire season".
The storm would improve fire conditions, but there were hot days forecast and all it only took two or three of those and all the new moisture would dry up.
Fenz monitored the situation daily and met up weekly to discuss any changes to the fire season.
"We keep a real close eye on the weather."
Fire conditions were based on three "triggers".
The first was how cured the grass was.
About 90% of Upper Waitaki’s grassland was cured, creating bad fire conditions.
The second was the build-up index, which measured how much available fuel there was to burn, such as grass and shrubs.
The last was the drought index, which gave a numerical value to how much moisture was in the soil.
A large-scale rain event would usually occur in the early months of the year, easing the fire restrictions, but there were yet to be any signs of that, he said.
MetService meteorologist Dom Barry said a band of rain was expected to pass over Otago this weekend, but the scale of it was still unclear.
It was likely to rain for a few hours on Saturday and early Sunday near Oamaru, but that would be the extent of it based on current predictions.
At this stage there were no predictions for a heavier rainfall and the fire risk would stay high for some time.
Mr Harrison said it was not just deliberate burns that caused vegetation fires.
There had been a string of blazes caused by heavy machinery, including a metal blade causing a spark and a hot piece of metal being left on cured grass.
Any outdoor chores that had the potential to cause a spark or heat should be done in the morning, when the air was cooler and there was some condensation on the grass.
