On kunanyi/Mount Wellington, 200mm of rainfall has transformed a rocky patch of forest into a striking pool. It’s freezing cold, but the water is clear and blue. The Disappearing Tarn appears only after a heavy downpour. It’s shrouded in a layer of mystery among visitors and scientists alike: geomorphologist Kevin Kiernan speculates its arresting blue colour may be a result of fine sediments in the water as it pools over depressions in the land. At the bottom of this basin, organic matter rots and occasionally releases bubbles. Bureau of Meteorology forecaster Matthew Thomas told the ABC there isn’t “a heap of scientific literature” on the formation, but that it tends to occur when more than 60mm of rain falls across a few consecutive days. Its rarity adds to the desire for local photographers and bushwalkers to witness it, often after multiple attempts of trekking through the bush. Since news of its reemergence spread earlier this week, Hobart locals have been donning puffer jackets and leaving their woodfire-warmed homes for a half-day pilgrimage, hoping to catch a glimpse of the natural phenomenon before it’s lost for another few months or years. The Tarn most famously appeared back in rainy 2018, when flooding in the state’s capital was declared a “natural disaster”. Many of the mountain’s tracks had closed, and some were seriously damaged. But the Disappearing Tarn was a tranquil beauty for those who could find it. “A bit like our lives, it’s transient,” says David Sinclair, a local photographer and occasional tour guide who has led journeys across the Arctic and Antarctica. He leapt at this year’s opportunity to visit the Disappearing Tarn, seeing it twice in just 24 hours. On his first trip, he spotted 30 people. During his second, he estimates there were more than 100. Locals – starved of interstate experiences and local thrills due to Covid-19 travel restrictions – braved the icy water for a dip. Even Sinclair joined in. On his way, he saw a flurry of cars at The Springs – the major stopping point on the mountain. It had never been busier. Parents carried babies on their backs as they navigated the rocks and mud, desperate to catch a glimpse of the site. “I think everyone’s curious to see new things,” Sinclair says. When those things are showcased on social media, the appeal tends to skyrocket. To their credit, many travellers confronted torrential rains to find the picturesque location. But Sinclair was alone when walking to “the far side of the Tarn” for a look at the less-photographed area. “The funny part was that if you walked another 40 metres over a hill, there’s another lake with no one there at all,” he smiles. “People are lazy. They just stop and don’t explore – they just go where everyone else goes now, with Instagram and Facebook.” There may be plenty of visitors, but there was “not a single piece of litter, no bad behaviour – everyone was really happy saying hello, and that’s what’s really nice to see”. Matt Davis was also drawn to his friends’ snapshots of the Disappearing Tarn. “I’ve walked there three or four times now trying to see it without any luck over a few years,” Davis says. After the latest downpour, the landscape photographer and firefighter “got a bit lucky” and finally found what he was looking for. He describes his time capturing theDisappearing Tarn as simultaneously “really very peaceful” and “raining quite hard”. As photographers and walkers share their perspectives of the Disappearing Tarn, it seems impossible for those who seek it to detach an existential view from this tiny body of water. “The Tarn stands out as different to all the others due to its ephemeral nature,” says Ally Skeels, an avid hiker. She and her husband Cam moved to the state in 2019, a year after reading about the Disappearing Tarn in the news. It became a “bucket-list item” for the couple. “I really wanted to see if the water was actually that colour,” she says. “It is.” Like Davis, Skeels had also made unsuccessful trips to the Tarn. Not this time. “There were others that were having a dip, so on the spur of the moment I decided to go in. Getting in was hard – my feet hurt with the cold from the moment I stepped in.” Another swimmer, marginally more prepared with goggles and a cap, would tell her he measured a temperature of just 5.9C at the edge of the surface. Skeels, who has previously swum in the Franklin River, and under a waterfall on the Overland Track, says this water was the coldest. “It is such a fleeting thing. You hike out there, and it may be there – or it may not. But if you hit the jackpot and get to see it in all its glory, it is so worth it,” Skeels says.