THE official declaration of a La Nina event, the first in nine years, suggests a high chance of above average rainfall across Victoria, particularly during spring and early summer, potentially filling farm dams but presenting an increased risk of flooding.
While catastrophic flooding occurred in Gannawarra and Loddon shires, as well as in many other parts of Australia, during the most recent La Nina event in 2010-11, this year’s La Nina is predicted by the Bureau of Meteorology (BoM) to be of lower intensity.
Last week the BoM upgraded its existing La Nina alert, declaring an active event, based on recent changes in ocean temperatures and weather patterns over the Pacific Ocean.
La Nina is associated with cooler than average sea surface temperatures in the central and eastern tropical Pacific Ocean, and typically results in above average rainfall for Australia, with the resultant weather impact usually most prominent during spring and early summer.
BoM manager of climate operations Dr Andrew Watkins outlined the likely effects on Victoria.
“During La Nina, south-eastern Australia typically gets more rainfall during spring and also into the summer months,” Dr Watkins said.
“More rainfall, wetter soils, higher rivers and more water going into our storages are all likely,” he said.
Dr Watkins explained that while this is positive news for many farmers, there is also an increased risk of flooding, including flash flooding.
Following last year’s devastating bushfire season, the expectation is that Victoria is less likely to be hit by extreme heatwaves this summer.
“Luckily it (La Nina) reduces the risk of getting those really extreme heatwaves, but unfortunately the hea waves we do get tend to be longer in duration and could be more humid as well,” Dr Watkins said.
“It reduces the fire risk a little but (with) south-eastern Australia one of the most fire-prone places in the world we’re not going to get through a summer without seeing any fires.”
