An intense tropical low which formed off the Pilbara cost yesterday brought unseasonal heavy rainfall and wild storms to the region.
Port Hedland experienced its wettest June day recording 140mm in the 24 hours to 9am and 209mm fell at Karratha.
John Holland machine operator Wayne Dransfield told The West Australian he was finishing up nightshift along Great Northern Highway on the outskirts of Port Hedland when his boss radioed him.
"He said, 'Guys, look over to your left. There is something on the way', and we looked over and it was heading straight for us," Dransfield said.
Dransfield, a fly-in, fly-out worker from Sydney said he watched in amazement as a twister ripped through a power line and road sign.
"One of our graders was parked and it blew out all the windows," he said.
Last week unseasonably wet weather forced Fortescue Metals Group to downgrade its production guidance for the financial year.
Fortescue said it would produce between 80 million and 82 million tonnes of iron ore for the 2013 financial year, down from its previous guidance of between 82 million and 84 million tonnes.