The current El Nino is now the strongest since the 1997/98 record event, according to the Bureau of Meteorology.

“The tropical Pacific Ocean and atmosphere are fully coupled, with sea surface temperatures well above El Nino thresholds,” its latest update says.

Temperature anomalies remain half a degree below the 1997/98 peak, but the tropical Pacific is expected to continue warming, with the largest anomalies occurring later in the year.

The United Nations’ World Meteorological Organisation (WMO) says this year’s event is the first since rapid melting of Arctic sea ice and snow cover.

“We have lost a massive area of northern-hemisphere snow cover, probably more than 1 million square kilometres in the past 15 years,” Director of the WMO co-sponsored World Climate Research Program David Carlson said.

“We are working on a different planet and we do not fully understand the new patterns emerging. We have no precedent.

“Climate change is increasingly going to put us in this situation.”

Meanwhile, the bureau says the Indian Ocean has been at near-record temperatures.

The Indian Ocean Dipole (IOD) index has been at or above +0.4 degrees for the past four weeks, but to be considered a positive event the IOD would need to remain at that level throughout this month.

Three out of five international models surveyed indicate a positive IOD event is likely during spring.

El Nino usually produces below-average rainfall over eastern Australia, while a positive IOD extends this pattern to central and southeast areas.

“However, sea surface temperatures to the north of Australia and more broadly across the Indian Ocean basin also affect Australia’s climate and are likely to be moderating the influence of these two climate drivers in some locations,” the bureau says.