It looks like a scene from a blockbuster movie - a menacing storm bearing down on boats on an eerily calm ocean.
The spectacular sight was produced by Mother Nature and captured on camera by tugboat workers off Onslow on Wednesday.
At sunset, a thunderstorm that had gathered dust and sand as it developed over Onslow passed across to the Indian Ocean, creating a breathtaking display.
Jurien Bay's Brett Martin, who was working on a tugboat west of False Island, snapped some stunning pictures on his mobile phone as the storm intensified.
"We were steaming along in the boat just before sunset and the storm was casually building in the distance, then it got faster and faster and it went from glass to about 40 knots in two minutes," Mr Martin said yesterday.
"I've never seen anything like it, it was pretty special and it was definitely an eerie feeling."
Isaac Kneipp, chief officer on the Westsea Gail anchor-handling tug, also captured the storm on his phone from a cyclone mooring about 28km north of Onslow.
"I have been at sea for 15 years and I've been through dozens of cyclones and heavy weather but this is one of the most visually spectacular I have seen," he said.
"The storm lasted about an hour and then went back to calm weather."
Weather Bureau duty forecaster Austen Watkins said the spectacle was created as wind and rain caused the storm to dump the sand and dust it had gathered while passing Onslow.
He said the storm brought gusts of up to 102km/h and was not unusual for the region in summer.
Mr Watkins said the storm was unrelated to looming cyclone Narelle, which intensified as it approached the Pilbara coast last night.
Parts of the coast from Whim Creek to Mardie have been put on blue alert, with gusts of up to 100km/h expected overnight and this morning.
Iron ore ports at Cape Lambert and Dampier were set to close and Apache shut the Stag and Van Gogh oil fields.
Chevron was evacuating workers from Barrow Island.
Last night, Narelle was about 630km north of Exmouth and 535km north north-west of Karratha and moving south south-west at 19km/h.