Rain likely to continue over summer

Some of the flooding around the Tumbarumba Creekscape area on Wednesday.

Tumut agronomist Nathan Ferguson says farmers in the Tumut region can expect more of what they have been getting as the Bureau of Meteorology has declared that a La Nina system has developed in the Pacific Ocean.

La Niña is part of a cycle known as the El Niño-Southern Oscillation (ENSO), a naturally occurring shift in ocean temperatures and weather patterns along the equator in the Pacific Ocean. It pushes clouds westwards to Australia, bringing rain and lower temperatures.

It means good and bad news for farmers.

“It will be wetter than normal and cooler than normal,” Mr Ferguson said.

“Rain is always good, but heavy rain and flooding on a water course is never good. In a general sense it is always better to be wetter than dryer.”

Unfortunately, weeds like rain just as much as pasture and crops, and the Tumut region is unlikely to be spared, so farmers will need to be prepared.

“There’s going to be a big Bathurst burr and blackberry problem,” Mr Ferguson said.

“If you didn’t spray last summer, then you are going to have a really big problem, and those who sprayed last year will need to spray again.”

Mr Ferguson said that for sheep producers, fly strike would be an issue in the wetter weather.

Up to yesterday (Thursday) morning, Mr Ferguson has recorded 1251mm of rain this year in Tumut, well above the long-term average of 886mm for a whole year.

He said that the rainfall would delay rather than eliminate the threat of bushfires.

“As soon as it dries out, you are going to have a huge amount of biomass,” he said.

“Also, making hay and sileage will be very, very difficult as it has been.”

The Bureau of Meteorology this week declared a La Niña has developed in the Pacific Ocean.

The Bureau’s Head of Operational Climate Services, Dr Andrew Watkins, said that typically during La Niña events, rainfall becomes focused in the western tropical Pacific, leading to wetter than normal period for eastern, northern and central parts of Australia.

“La Niña also increases the chance of cooler than average daytime temperatures for large parts of Australia and can increase the number of tropical cyclones that form,” Dr Watkins said.

“La Niña is also associated with earlier first rains of the northern wet season, as we’ve observed across much of tropical Australia this year.

“The last significant La Niña was 2010–12. This strong event saw large impacts across Australia, including Australia’s wettest two-year periods on record, and widespread flooding.

This included the Adelong floods of 2010 and Tumut floods of 2012.

“La Niña also occurred during spring and summer of 2020-21. Back-to-back La Niña events are not unusual, with around half of all past events returning for a second year.”

Dr Watkins said that this year’s event is not predicted to be as strong as the 2010-12 event and may even be weaker than in 2020-21 La Niña event.

“Every La Niña has different impacts, as it is not the only climate driver to affect Australia at any one time. That’s why it is important not to look at it in isolation and use the Bureau’s climate outlooks tools online to get a sense about likely conditions for the months ahead,” Dr Watkins said.