Mother Nature has thrown Auckland's peak-hour commute into chaos today as a Harbour Bridge traffic jam stretches kilometres and the Northwestern Motorway also faces delays.
It's meant motorists heading home to the North Shore and western suburbs face long delays that are only likely to get longer during Friday's afternoon commute.
A freak burst of wind during a blast of stormy weather earlier caused the problem when two trucks were blown into structural frames on the Harbour Bridge at about 11am.
The crashes shut down all northbound motorway lanes on the bridge for close to 30 minutes and saw traffic slow to a crawl for several kilometres.
The NZ Transport Agency and emergency teams managed to reopen two lanes by 1pm but advised motorists to avoid the Harbour Bridge if possible, suggesting taking the SH16 Northwestern Motorway route as an alternative.
"Please delay your journey north or consider using SH16/18 as an alternative," NZTA said.
However, with diverted traffic on the Northwestern also backing up, NZTA is now asking motorists to avoid travelling until later if possible.
A crash on the Northwestern eastbound link from SH16 to SH1 also delayed motorists.
NZTA traffic maps showed very heavy traffic from at least the St Luke's off ramp to the Lincoln Rd off ramp.
"Due to the truck crash on the Harbour Bridge traffic diverted from SH1 is now producing very heavy flows on SH16 (Northwestern Mwy). Please DELAY YOUR TRAVEL or expect delays this afternoon," it said.
NZTA said it had structural engineers assessing damage to the bridge.
"More information will become available as soon as this assessment is complete," it said.
NZTA Auckland system manager Andrea Williamson earlier said that just after 11am the wind was gusting at just over 60km/h, but suddenly picked up to blow at up to 127km/h for several minutes.
"A medium-sized truck travelling in lane 3 northbound was hit by a strong gust of wind and blown across two lanes. It toppled over the moveable lane barrier and is now stuck on the barrier. The driver was not injured."
The truck was from courier company Castle Parcels.
"At the same time a southbound truck carrying a shipping container was blown sideways and hit the bridge superstructure," Williamson said.
"The truck righted itself and carried on.
"There is damage to the bridge over arch, with a steel upright sheared off.
"The four lanes in the bridge centre span will remain closed until the damaged upright is assessed and repaired."
A St John Ambulance spokesperson said one person was being taken to North Shore Hospital in a moderate condition.
St John was alerted at 11.10am. One ambulance and two managers tended to the injured person.
Recovery of the truck wreckage is expected to take several hours.