Wind vs the temporary events structure

Wind. It’s a topical subject right now here in Wellington, New Zealand as we are cleaning up from hurricane force winds that last week had the anemometer readings tipping 200km/hr on the biggest gusts. Down at our local park a massive macrocarpa tree has been uprooted and lies across the car park. Across town windows have been blown in and roofs removed. On the south coast the sea wall has been breached and the force of the wind and sea has ripped up the roads and damaged property.

Ironically on Thursday night, as our lounge windows flexed and roof tiles rumbled with each strong gust, I was reading a Linkedin group post about an event structure collapse in high winds in Phuket, which killed one person (Phuket marquee collapse). This was related to similar posts of event structure collapses in the United States and Europe. The latest was posted only yesterday (Swiss marquee collapse)

With the storm raging outside I was made acutely aware that there wasn’t much that could be done there and then to secure our property. I wouldn’t even be able to stand upright if I went outside, let alone climb a ladder to attempt to secure whatever it was that was flapping around so noisily on the garage roof. A quick informal risk assessment had me rating the likelihood of being flattened by a broken off tree branch or a neighbour’s wheelie bin before I took two steps outside as “pretty jolly high”. Coupled with the likely consequence of this resulting in “a considerable amount of pain”, I opted to avoid the risk altogether and stay inside.

So I was thinking, if I am seriously questioning whether our “permanent” structure garage is going to make it through the night what chance is there for any temporary event structures in these conditions? The likes of stage roofs, marquees, port-a-cabins, port-a-loos, big screens, big top circus rigs and lighting towers?

The reality is no amount of regulations, structural design, building consents, worker competency, maintenance schedules, load testing or engineer sign-off will guarantee the protection of a temporary event structure from the wrath of severe gale force winds. By all means we need to spec these structures as best as we can for the potential conditions (and in Wellington it’s not uncommon to have wind gusts over 100km/hr), and fulfil our duty of care with regards to regulations, consents and sign offs. AND we also need to ensure contingency planning is in place to deal with the residual risks that remain due to human error or extreme conditions. We need a schedule of monitoring, decision-making and communication structures, cancellation policies and procedures, and evacuations plans (complete with isolation zones).

Looking out the window last Thursday night at the violence of the storm that was battering Wellington reinforced to me that standing in a hurricane is neither the time nor place to be developing your contingencies. This requires advanced planning, communication and practice so when conditions turn extreme we have the opportunity to save lives even if we cannot save property.

So it was on Thursday night with the garage roof flapping and house windows flexing I abandoned all thoughts of DIY maintenance and headed to bed with my torch and phone; shoes and jacket nearby and a crudely devised evacuation plan to head downstairs to the basement office should the roof fly off.