Most severe flooding in eastern Australia seems to have passed: AIR Worldwide

Dozens of flood warnings in eastern Australia remain in effect, although heavy rainfall associated with ex-tropical cyclone Oswald and enhanced by a monsoon trough has receded, and the most severe flooding seems to have passed, AIR Worldwide reports.

The monsoon trough, an elongated area of low pressure, moved south along the Queensland coast into New South Wales, the catastrophe modelling firm notes in a statement issued Tuesday. Resulting floodwaters cut off rural communities, damaged homes, caused massive power outages and disrupted coal mining operations, the statement notes. In addition, thousands of residents have been forced to evacuate their homes.

“Despite weakening below tropical cyclone status, heavy rainfall has been observed along the entire east coast as the slow-moving system, enhanced by a monsoon trough, tracked south and east along the coast,” Peter Sousounis, senior principal atmospheric scientist at AIR Worldwide, says in the statement.

Citing figures from NASA’s Tropical Rainfall Measuring Mission satellite, AIR Worldwide reports the ex-tropical cyclone has dropped more than 600 mm of rain in areas of the Cape York Peninsula where the cyclone initially made landfall. “As the remnants tracked south, heavy rainfall has continued along the coast, with more than 300 mm observed over portions of northern Queensland, and more than 400 mm north of Brisbane in southern Queensland,” the statement adds.

Four-day rainfall records were set in the coastal Queensland city of Gladstone, with 819.8 mm, and in the Tweed Catchment of the Upper Rous River in NSW, with 1,027 mm.

“The most severe of the flooding occurred in the Burnett River catchment area near the Queensland coast. River levels exceeded 9.5 meters, surpassing the height reached during the last significant flood in December of 2010 by 1.5 metres,” Sousounis notes.

Although the latest floods are reminiscent of the devastating 2010-2011 Queensland floods, AIR Worldwide reports, the impact is expected to be far less severe. The floods two years ago covered more than half of the state, with economic losses estimated at $30 billion and insured losses at $2.4 billion resulting from an estimated 60,000 claims (all figures in Australian dollars).

This time around, effective flood defence mechanisms have protected, thus far, most communities in NSW from significant flooding. Sydney is not expected to be affected by the flooding, AIR Worldwide reports.

On Jan. 29, the Insurance Council of Australia (ICA) issued yet another disaster declaration, the fourth so far in 2013, for the Tweed and Northern Rivers regions and coastal areas of NSW from the Queensland border to the Illawarra.

Council CEO Rob Whelan said at the time there were thousands of callouts for storm damage. “Claims numbers in NSW are modest, though we would expect to see an increase in inquiries to insurers’ call centres over the next 24 to 48 hours as property owners assess any damage caused by the extreme weather.”

Many NSW communities were fortunate to have well-designed and well-maintained physical mitigation infrastructure, such as levees, in place to protect them from rising rivers, Whelan added.

The ICA reported that as of 7:30 am on Jan. 29, insurers had received about 6,100 claims related to the Queensland floods, with losses estimated at $72 million. By 10 am on Jan. 30, claims received had increased to 21,900, with estimated insured losses of $187 million. The 2,000 claims from the NSW floods had estimated losses of $10 million.

“We expect these numbers will rise as more property owners lodge claims and assessors start to enter residential and commercial properties that have been inundated by flood waters,” Whelan says in a statement.

On Jan. 30, insurance assessors had started to enter flood-affected towns in Queensland. Whelan notes that the industry was focusing on accelerating the claims process to help flood-affected policyholders to recover.

ICA reports that claims received relate to typical storm damage, such as damaged vehicles and overflowing gutters, and inundation of properties.