Fears rise for homeless and vulnerable people as communities brace for another week of relentless hot weather

It was 48.9C last Tuesday in Port Augusta, South Australia, an old harbour city that now harvests solar power. Michelle Coles, the owner of the local cinema, took off her shoes at night to test the concrete before letting the dogs out. “People tend to stay at home,” she said. “They don’t walk around when it’s like this.”

It’s easy to see why: in the middle of the day it takes seconds to blister a dog’s paw or child’s foot. In Mildura, in northern Victoria, last week gardeners burned their hands when they picked up their tools, which had been left in the sun at 46C. Fish were dying in the rivers.

Almost every day last week a new heat record was broken in Australia. They spread out, unrelenting, across the country, with records broken for all kinds of reasons – as if the statistics were finding an infinite series of ways to say that it was hot.

The community of Noona – population 14 – reached the highest minimum ever recorded overnight in Australia – 35.9C was the coldest it got, at 7am on Friday. It was 45C by noon.

A record fell on Tuesday in Meekatharra in Western Australia – the highest minimum there ever recorded (33C). Another fell on Wednesday, 2,000 miles away, in Albury, New South Wales – their hottest day (45.6C).

It was 45C or higher for four consecutive days in Broken Hill – another record – and more than 40C for the same time period in Canberra, the nation’s capital. Nine records fell across NSW on Wednesday alone. Back in Port Augusta, Tuesday was the highest temperature since records began in 1962.

In the Niagara Cafe in Gundagai, whose claim to fame is that the former Australian prime minister John Curtin once popped in during the second world war, Tina Loukissas turned off the deep fryer, then the grill.

“It feels like you’ve walked into a sauna,” she said. “When it’s getting up to 43C or 44C, because you have all these machines going, the air conditioning isn’t coping very well.

“We’ve got tables outside that nobody has sat at for the last couple of days … You’d be crazy to sit outside on a day like today.”

In Mildura, Tolga Ozkuzucu, owner of Top Notch Gardens, had the misfortune to be working outdoors.

“It’s been like hell,” he said. “You have to try to leave your tools in the shade. If you don’t, it burns your fingers. There’s not much you can do.

“I try to start as early as I can. I’m not going to risk my body and health. People here are very understanding of that because they know how hot it is … nobody wants to be outside when it’s 46C.”

In South Australia, they declared a “code red” across Adelaide, the state capital. Homelessness services were working overtime and the Red Cross started calling round a list of 750 people who were deemed especially vulnerable.

At the Australian Open in Melbourne, only the sea breeze kept the temperature below 40C. At Adelaide’s Tour Down Under, a bike race, it was 41C.

On Monday last week the hottest spot in New South Wales was Menindee, a river town that feeds the country’s largest water system, the Murray-Darling basin. It was 45C. It climbed to 47C on Wednesday, and by Thursday the fish were gasping.

Australia’s native Murray cod can live for decades under normal conditions, growing all the while. The oldest are a metre long, with heavy white bellies that have to be held with both hands. Last week, hundreds died, choked of oxygen due to an algal bloom that fed and grew in the heat, and collapsed when temperatures dipped.

Play Video 'Bloody disgrace': '100-year-old' fish die in Darling River – video

Blue-green algae flourishes in hot, slow-moving water. Then, when temperatures inevitably drop, the algae dies and becomes a food source for bacteria, who multiply and starve the river of oxygen. The fish rise to the surface.

The mass fish death has reignited a debate over water management in the region, where cotton farmers upstream have been accused of taking more water than they should.

The heat is not the root cause, the locals stress. But the five punishing days settling over the river have not made it better. Last Thursday the cod were up near the surface and struggling. On Friday, it was 45C again. In Menindee, the locals believe the fish kill will happen again, with temperatures in the 40s expected to continue into this week. The water will be running hot.

But away from the Darling, Michelle Coles from Port Augusta says she is used to the heat.

“I didn’t think it was that hot yesterday, if you want an honest answer,” she said last Wednesday, the day after the temperature hit 48.9C.

“Yesterday at the cinema, it was very quiet. People tend to stay home. We’re quite used to it. Once it’s over 40, it’s hot.

“We’re conditioned to it. Honestly, I’d much rather be in 48C heat in Port Augusta than in the city. You’ve got so much concrete and it’s closed in, but here it’s quite open.

“You just don’t stand out in the sun though. That would be stupid.”