Been there, seen that movie.

More video has emerged of the Auckland Harbour Bridge clip-on lanes swaying as people walk on them

Poor snowflakes, a real life experience.  Been there, seen that for real in a car.  

More than a few decades ago, I had the misfortune to be heading southward across the same bridge on the outer clip-on three or four behind a high sided furniture truck that tried to lurch sideways off the bridge just short of the crest.  A half decent gust (normal for Jafaland weather, not a climate change induced extreme) from the south west caught the truck, knocked it flat and nearly succeeded in launching it over the guard rail.  About 170 feet to water below.  Note quite dead ants but so close.

The areas around those arches were well known to those who travelled the bridge daily as an area that produces serious vortexes and eddies.  In later times, crossing on a 90cc Suzuki daily taught one to be even more careful.

Needless to say as emergency services arrived some considerable time was spent stopped in the traffic observing the ever changing large gap between the clip-ons (steel deck on steel legs on rollers at piers - can move considerably) and the original concrete deck (solidly fixed to Northcote Point just at the start of the main arch works).  Being in a stopped vehicle induced a sea sickness like feeling during the solid but normal gusts.  For expansion and wind gusts, the clip-ons are separated and do move independently to the original four lanes.