Spectacular vision of a twister-like whirlwind that sent a tent swirling into the sky, damaged a roof and forced a group of mates playing golf to take cover in the Northern Territory town of Katherine, has been identified by the Bureau of Meteorology as a rarely seen phenomenon called a gustnado.
"They look a little bit like a dust devil, but they're not," the Bureau of Meteorology's senior meteorologist Sally Cutter said. They are stronger.
Just before sunset on Friday, as dark storm clouds and booming thunder rolled across the remote town, 300km south of Darwin, a gust front whipped up a column of rising and rotating air, a bit like a vortex, picking up debris along the way, Ms Cutter explained.
Videos posted to social media show a tapestry of debris and dust twisting through the sky over the CBD, the busy Stuart Highway and a golf course.
The gustnado is not considered a true tornado or a twister by most meteorologists, but is rarely observed.
"It's probably an unusual event to actually see," Ms Cutter said.
"That's not to say they're not out there ... you just don't see them because the storms are occurring in remote areas of the Territory."
They are so rare in urban spaces, Ms Cutter said records of the unusual events were rarely documented.
"It's probably something that is not often observed at the various airports, which is where we've got the manual observers, so we don't really have those records to say when the last one was observed," she said.
"It was certainly spectacular, you've just got to be in the right spot at the right time to see some of these phenomena.
"I've seen a massive dust devil at the Alice Springs Airport, and you just had to be out there at the right time, because it didn't last that long.
"So to actually see these phenomena and then [for it] to be captured is quite amazing."
A 'pretty intensive' storm makes a beeline
John Maclagan, who captured the video during a game of golf with some mates, said the gustnado looked fairly innocuous at first. But then it made a beeline for the group and they quickly took refuge.
"It headed across the park, picked a tent up, we started filming it and having a bit of a giggle, not knowing where it was going," he said.
"We didn't really have anywhere to go, so we took cover and the winds got real strong.
"It pushed one of our buggies off, took the seat off and took an esky full of drinks out of the buggies and threw it across the ground.
"It was pretty intensive. We were a little excited as you can see in the video."
Increased storm activity for Top End
The Northern Territory is in the middle of its annual hot and sticky wet season build-up, and despite multiple torrential downpours across the Top End over the past few weeks, the monsoon is yet to officially start.
It has been a run-of-the mill wet season so far, according to Ms Cutter, who says a trough moving north over the next few days is expected to increase storm activity for the Top End.
"During the wet season, we do go through these periods of active storms and then we'll have a bit of a low and then we'll get some more active storm period. So it's what we'd expect for the build up type conditions," she said.
