Climate models are suggesting above average winter and spring rainfall is possible this year, with the potential for a waning La Nina to be followed by another wet weather driver.

The Bureau of Meteorology says the 2021/22 La Nina continues to weaken and six of seven climate models surveyed indicate a return to neutral conditions in the Pacific Ocean during the late autumn or early winter.

But outlooks for the Indian Ocean Dipole (IOD) show a negative event developing in coming months, increasing the chances of above average winter-spring rainfall for much of Australia. The IOD is also associated with warmer days and nights in the country’s north.

“While model outlooks have low accuracy at this time of year and hence some caution should be taken with IOD outlooks beyond May, there is consistency across the forecasts from all international models,” the bureau says.

The past summer continued the trend set by a wet spring, with the La Nina event leading to increased rainfall and warm ocean temperatures on the east coast of Australia, the Actuaries Institute says.

The Australian Actuaries Climate Index, released quarterly, says the La Nina event affected sea levels as a result of warmer water expanding.

The sea level index was above a reference period average for every part of the country and the latest period marked the 24th consecutive season where it was positive for the country as a whole, the Actuaries Institute says.

The Murray Basin, covering parts of NSW, Victoria and SA, set a record for the extreme low temperature index this summer, indicating warmer minimum temperatures. The trend was also seen in the Southern Slopes Victoria region.

The Actuaries Institute Climate Index measures changes across 12 Australian regions, with data compared to the same season previously and against a reference period from 1981-2010.

The catastrophic rainfall that hit Queensland and NSW from late February didn’t set climate index records for the East Coast North and East Coast South areas, given the broad focus of the index and its three-month timeframe.

A Risk Frontiers briefing paper says 40 people have died from floods over the La Nina period from November, while there have also been numerous instances of near misses and dramatic rescues.

Two thirds of the deaths were due to cars driving through or being engulfed by floodwaters. Other causes included being in a house engulfed by water or mudslides, being washed away while on foot or falling from a watercraft.

Consecutive La Nina events in 2010/11 and 2011/12 led to a total of 48 flood deaths, while there have been at least 167 deaths in Australia due to flood from the 2011 financial year to the current year.