The Bureau of Meteorology issued a La Nina alert last week as the type of rainfall and severe weather typically associated with the seasonal event and other climate drivers affected much of eastern Australia.

The bureau moved to a La Nina alert, from a watch, due to continued cooling in the tropical Pacific Ocean and an increase in the number of climate models showing sustained conditions linked with the event over summer.

La Nina events, which increase the chances of above-average rainfall for parts of Australia during spring and summer, typically develop around 70% of the time after alert criteria are met, which is about triple the normal likelihood, the bureau says in a Climate Driver update.

“With an already wet landscape and above average rainfall likely, there is an increased risk of widespread flooding for eastern and northern Australia,” Senior Climatologist Greg Browning said.

Australia has recently been affected by a weak negative Indian Ocean Dipole, which is also associated with above-average spring rainfall, while the Southern Annual Mode is also expected to return to positive rain-inducing territory.

A tornado was last week reported in the NSW regional city of Armidale, heavy rainfall and hail affected parts of western Sydney, while severe thunderstorm warnings have been issued in Queensland.

Insurers say the storms were not significant from a loss perspective, but they have generated a number of calls from policyholders. IAG on Friday said it had received around 1300 claims.