How much wind could knock the Sky Tower over?

Just how much wind can Auckland's iconic Sky Tower take?
Just how much wind can Auckland's iconic Sky Tower take? Photo credit: Getty

Tuesday's storm took off roofs and blew down trees - but how much wind would be capable of knocking over the Sky Tower?

The Southern Hemisphere's tallest freestanding structure and the defining feature of Auckland's skyline, the 328m building has seen its fair share of wild weather since opening to the public in 1997.

But just how strong a wind is the Sky Tower built to withstand?

The peak wind in Auckland during Tuesday night's squall was a whopping 213km/h at Manukau Heads, although MetService says the extremely exposed area isn’t representative of the average winds experienced.

SKYCITY senior communications advisor Rebecca Foote says even during the strongest gusts on Tuesday night, Sky Tower staff weren't worried.

"There was no concern from a wind perspective," she told Newshub. "It's stood for 20 years."

The tower can handle extremely high winds. It would start having trouble at speeds of 200km/h - a freak weather event only expected to happen once every 1000 years.

In high winds, the Sky Tower's elevators will reduce their speed by half or even return to ground to wait it out.

During an intense storm in 2006, the Sky Tower could be seen visibly swaying in winds of 140km/h. Ms Foote says the upper concrete shaft might move as much as 1m side to side in very strong gusts

The gangly structure's surprising durability is thanks to its strong foundations, which go more than 15m below ground and spread force load so the tower can't be toppled by even the most powerful of Auckland's winds.

The Sky Tower was struck by lightning during the storm, another weather event it's well-equipped to handle. The conducting dynasphere at the top of its signature mast means visitors are protected from any rogue bolts.

Even a severe earthquake right in the centre of Auckland couldn't take down the tough tower.

"Analysis also shows that the Sky Tower would remain standing in an earthquake measuring 8.0 on the Richter Scale occurring within 20km of the Tower," Ms Foote says.

It's safe to say the Sky Tower will stay on Auckland's horizon, charging tourists $17 for a cocktail, for the foreseeable future.

Newshub.

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