Seeing a horse and rider swallowed by quicksand is a moment Eunice Atkins will not forget.
“The horse went down, up to its ears … in one hit, it just went ‘whump’ and disappeared,” she said.
It is one of many encounters Ms Atkins has had with quicksand on the west coast of Tasmania, a renowned hotspot for the hazard.
This particular encounter ended with both man and beast quickly retrieved, but hundreds of quicksand experiences here have not ended so well.
For many people, quicksand is confined to the screen, in films like Jumanji and The Princess Bride.
But it is a very real — and not even rare — geomorphological feature, explains consulting geologist, John McDougall.
It occurs wherever the fine sand at the bottom of a gently flowing river or stream has water flowing not only over it, but through it.
In Tasmania, these spots lie mostly on the west coast, between Pieman Heads and Arthur River, and they only act as quicksand when disturbed, for instance by an animal or vehicle.
For the owner of the feet or wheels on top of the sand, this means sudden sinking.
Horses, dogs fall victim
While human lives seem not to have been lost in the quicksand of this area, plenty of animals have perished.
Local retired police commander Lachlan Avery said that when cattle were mustered along the coastline here, many met their fate in the sand.
“When I was younger, it was nothing to go along the beach and see where a cow had been caught in the quicksand,” he said.
“There’s been vehicles lost down there with dogs in them.
And, like the rider in Ms Atkins’s story, Mr Avery has hit quicksand on a horse.
“As he went down I just jumped off his back and tried to pull at him,” he said.
“He managed to flounder himself around and come back out of it … thank goodness.”
Entire convoy submerged
Vehicles of all kinds also regularly get stuck in quicksand in this area, although no one can guess how many times in total.
Ian ‘Snow’ Nielson, a retired paramedic who worked in the region for 50 years, says the number is “a lot”.
The sand here has even enveloped tractors.
Mr Nielson remembered one day he advised the leader of a four-wheel drive convoy not to drive along a dangerous beach.
“The lady sitting in the passenger seat said, ‘Why not?’ and I said, ‘Because the sea is wrong; the tide’s coming in, and the sand will be soft’,” he said.
The next day Mr Nielson was called to the ranger’s hut in Sandy Cape.
“This lady came out and she said, ‘He didn’t take any notice of you, did he?’,” he said.
The convoy lost all four of its vehicles in quicksand.
Invisible ‘traps’ swallow cars
Devonport 4WD Club member, Brian Imlach, said attempts to travel across quicksand often occurred because travellers did not know it was there.
“We just drive across it, and next thing we know, we’re down to our belly,” he said.
“You look at your wheels and you see this water shimmering, coming up through the sand, and you think, ‘God, I’m in trouble here’.”
Another reason quicksand is a threat is it moves around.
One week a beach can be firm and dry, and the next, with different wind, tide and sea conditions, the rivers will likely have changed their courses, moving the quicksand with them.
“They can be up to a kilometre in a different position,” Mr Imlach said.
“So, that’s the trap.”
Visitors disregard warnings
The final reason people attempt to cross quicksand is they underestimate it as a threat.
Many four-wheel driving visitors to the area have made costly mistakes due to not taking local stories seriously.
“They laugh at you and say, ‘What are you talking about? There’s no threat’,” Ms Atkins said.
Mr Nielson has been taking four-wheel drives along the West Coast for six decades but has no time for drivers with “bravado”.
“They’re the ones that get into trouble.”
Suction that can ‘break vehicles in half’
As for getting out of quicksand, that is easier said than done.
“You really, really struggle to get [stuck vehicles] out because the suction is that strong,” Mr Imlach said.
“I’ve seen them with six vehicles pulling at once, trying to winch a vehicle out.
“The vehicle would weigh 10 times as much as what it normally would.
Mr Avery said stuck vehicles needed to be rolled over.
“You can’t break that suction, so they actually roll them,” he said.
“But that basically buggers the vehicle.”
So, how to avoid getting stuck in the first place?
The critical thing is to talk to rangers or locals who know the coast before travelling.
“They won’t be telling you exaggerated stories,” Mr Nielson said.