Just look at that almost unbelievably long plume of thick dust stretching all the way from Central Australia out into the Indian Ocean hundreds of kilometres off northwest WA – a distance of around 1800 kilometres.

The remarkable dust storm occurred on Sunday afternoon, December 10, with airborne particles still clearly visible over the ocean this Monday morning.

The video below shows the event unfolding, with the heaviest concentration of dust centred over Western Australia’s Kimberley region, with lesser amounts over the Pilbara, a little further south and east.

What caused the dust storm?

The huge uplift of desert dust was caused by a trough which pushed well into northern WA over the weekend, strengthened by the low pressure system near SA and a high pressure ridge to the south.

This fairly unusual summer pattern brought strong and gusty southerly winds all the way through the desert and off the Kimberley coast, kicking up dust as it rolled through.

An interesting side-effect of those southerly winds and airborne dust was that some of Australia’s most consistently hot places had a relatively cool day by their standards on Sunday. For example:

Marble Bar in the Pilbara reached "only" 36.9°C on Sunday, more than five degrees cooler than the average December max of 42.1°C, and the first day below 40°C in December 2023 to date.

Fitzroy Crossing in the Kimberley reached "only" 35.1°C which was also by far its coolest day in December 2023 to date, and more than four degrees below its December average max of 39.3°C.

Serious summer heat will return to the area by the weekend, with Marble Bar looking at 45°C on Saturday.