The Insurance Council of Australia (ICA) is monitoring the impact of a severe storm that damaged property and left SA without power last Wednesday, while businesses are assessing interruption costs from the electricity outage.

High winds felled trees and caused transmission lines to topple, with cascading events triggering the state blackout. Rivers and creeks flooded as rainfall returned to already drenched areas.

Early insurer reports to ICA largely indicate low-level property damage across a widespread area, with a more complete picture still to emerge

But Australian Industry Group CEO Innes Willox says total costs may run into hundreds of millions of dollars, including start-up, clean-up and repair bills.

Power provider ElectraNet said yesterday most of the network has been restored, but some large industrial customers remain without full power.

Metals company Nyrstar says the power failure halted its Port Pirie smelter and the blast furnace will be down about 10-14 days for repairs. Metals processing earnings before interest, tax, depreciation and amortisation will be hit by about €3-5 million ($4-7 million).

OZ Minerals says electricity transmission to its Prominent Hill project will be progressively restored in the next 7-10 days, with disruptions affecting an underground mine and the processing plant.

The Olympic Dam mine run by BHP Billiton and the Whyalla steelworks are among other businesses hit by the outage.

The storm followed flooding around Forbes in central west NSW, with ICA earlier last week declaring that event a catastrophe after the Lachlan River inundated properties.

The Financial Ombudsman Service (FOS) has declared the NSW floods a significant event, and says it is liaising closely with ICA.

The FOS significant event response plan is activated for events that can lead to many disputes.

“It provides for early communication with relevant stakeholders and a more streamlined, expedited process for the resolution of related disputes,” FOS says.

Heavy rain across SA, Victoria and NSW last month followed Australia’s second-wettest winter on record.