A new report has found buildings in south-east Queensland and northern New South Wales would only be able to safely withstand weather slightly more severe than what was experienced during ex-Tropical Cyclone Alfred earlier this year.
Waterproofing, electricity and communication, and balcony pavers on high-rise buildings were identified as potential risks in the damage assessment conducted by James Cook University and Natural Hazards Research Australia.
Ex-Tropical Cyclone Alfred brought winds of up to 100 kilometres per hour when it crossed the coast at Moreton Bay on March 8.
A roof was blown off a building on the Gold Coast during the weather event. (Instagram: twp_fit_spo)
Report co-author Dr David Henderson said the system, which was downgraded from a category two to an ex-tropical cyclone as it made landfall, highlighted ways communities could better prepare for future events.
“One of the things that we want people to understand is that this was a great practice run in the event a stronger cyclone does eventually arrive in this area,” Dr Henderson said.
“This has happened in the past.”
Pavers could become dangerous projectiles
The report identified the use of pedestal-mounted balcony pavers as an area of concern, with fears they could become dangerous projectiles in winds higher than 100kph.
The paving slabs are elevated above the floor to enable drainage, but the report found the technique leaves them vulnerable to high winds.
“These pavers sit on these plastic stands, which is great and makes it nice and level, accessible,” Dr Henderson said.
“But because the pavers aren’t attached to the plastic stands, we’ve seen these winds now come across that are starting to lift some of these pavers.
“So if you could imagine the wind being 20, 30 kilometres per hour more — which is still less than what was originally forecast — we would have seen a lot more of these picked up and thrown around, which could have been quite problematic.”
The report recommended the pavers be fixed in place and standards revised to require each paver be sufficiently anchored to its building.
Power supply and waterproofing needs improving
Power supply was also identified as having room for improvement in the report.
It noted the potential for basements to flood during severe weather events would mean pump systems may need to be run off backup power in the event of a failure in mains electricity.
“It’s also important that sufficient power [is] available to run lifts to enable people with mobility issues to leave their apartments,” Dr Henderson said.
Weatherproofing could also be improved, with the report finding water entered a large number of buildings in the impact zone through roofs, closed windows, walls, and basements.
It recommended waterproofing concrete walls with external membranes to prevent water soaking through, and imposing standards on windows that prevented leakage during severe weather.
“If you look on the inside of the window, under the sill, there’s little holes along there … when there’s condensation or the moisture on the inside of it, it’s meant to run down and then flow out through those little holes,” Dr Henderson said.
“When we have storms that are bringing the rain that’s falling horizontally, because there’s now wind pushing it … it’s actually forcing the water through our window seals, and through those little weep holes, back up over the sills and into our buildings.”
Dr Henderson praised the community for its preparation but pointed out the potential for loose items to become missiles in high winds.
“It was really great to see a lot of people taking all this stuff off the balconies of the high rise apartments, cleaning up their yards, tying stuff down, doing all the pruning, it was like being back home up north,” he said.
“For a region that doesn’t have the same level of familiarity that we do in north Queensland when it comes to cyclone preparation, it was good to see people were paying attention to the messaging and were helping to protect their own and the neighbours’ places.”
He said ex-Tropical Cyclone Alfred was a good way to identify vulnerabilities in the region’s storm preparedness “without too much of the community having to suffer”.
“It was a ‘near miss’ and we must work hard as a community not to be complacent and put in place what is needed to minimise damage in a future stronger event.”
