Australia Weather News

Underestimating the wrath of the Australian sun and heat can have devastating consequences, a truth laid bare by two recent tragic incidents.

While it is now ultimately in the hands of the Northern Territory and West Australian coroners to determine reasons behind the deaths of German tourist Monika Billen and WA mother-of-two Felicity Shadbolt, whose bodies were discovered in separate outback investigations last week, both offered a stark reminder of nature's fury.

Thousands of kilometres apart, the two outback deaths had at least one thing in common — they both took place during a period of roaring summer temperatures around 40 degrees Celsius.

Searches around the Pilbara mining town of Tom Price, for Ms Shadbolt, and on the outskirts of Alice Springs in NT, for Ms Billen, were both undertaken in extreme heat.

Both women were believed to be out undertaking physical exercise at the time of their disappearances.

The temperatures in the two regions peaked at 46C and 43.5C respectively that day.

WA police have said they were not treating Ms Shadbolt's death as suspicious.

A report on Friday suggested she may have suffered a medical episode during the intense heat.

Ms Billen's body was recovered on Wednesday, and in her case, the extreme heat appeared to have taken a fatal toll.

Scientist warns of consequences

Award-winning heat stress expert Matt Brearley, from Darwin's National Critical Care and Trauma Response Centre, has warned of the deadly consequences that can come from bushwalking or physical exertion in such extreme temperatures.

"The [outback] is extremely hot and dry," Dr Brealey said.

"And when it's excessively hot such as 42 degrees, anything up in the high 30s and low 40s … our body tends to have to have trouble dissipating its heat.

"Which, for a person sitting under a tree having not done any physical work, it's less of an issue.

"But if you're out moving your body, hiking out over long distances and producing heat, that heat has to leave your body, otherwise your temperature will rise."

Soon, if the exertion continues, Dr Brearley explained, the body will begin to react. The sweat rate picks up.

The body will send blood to the skin.

"[That's] usually a good idea because the air around our skin is meant to be cooler than our skin temperature … but when it's so hot then we absorb heat that way, unfortunately," he said.

Symptoms heighten and can become deadly

As the body temperature rises, the effects become heightened.

For bushwalkers who don't have access to "heat loss behaviours", like finding some shade or turning on the air-conditioning, the dangers grow substantially.

"Given that that's not available to the bushwalker … they may have hiked three or four kilometres in, they're now starting to feel the effects of the heat," Dr Brealey said.

"They're quite a way from any aircon … they may be really motivated to push on and get to where they're seeking to get to.

"And if they're feeling the effects of the heat, they may not make the most logical decisions in getting there.

"They may not understand or process that it could be a life-changing event if they continue to produce heat and keep walking."

It's not long before the symptoms worsen.

Headache, nausea and lethargy can start to creep in.

"In some cases, people are so motivated that they will ignore those symptoms, or not even feel them," Dr Brearley said.

"[The symptoms are] there, but [the hiker is] so focused on making it to that certain point or getting to a certain view that they'll push on — to the point where their body stops functioning, where they can't continue walking."

The situation can quickly become critical.

Disoriented, overheated and on the verge of collapse, the body's central nervous system begins to break down.

The severity of symptoms increases.

Severe vomiting, collapse, seizures and, in the worst case scenarios, death are often the final outcomes for those who have succumbed to the outback Australian heat in all its scorching ferocity.

Planning can avoid 'crucial errors'

Dr Brearly's comments come as the public continues to ignore frequent urgent warnings from NT police, paramedics and park rangers to avoid bushwalking in the scorching Central Australian heat.

Last week, a 60-year-old woman had to be rescued while hiking the Larapinta Trail, west of Alice Springs.

She was with a bushwalking group when she sustained an ankle injury and became dehydrated.

Earlier in the summer, two groups of tourists were found suffering from heat stress in remote Central Australia, including three adults with a toddler.

Dr Brearley, who was last week named as the Accredited Exercise Scientist of the Year, said heat strokes were often brought on by a lack of planning or a reluctance to change plans.

"I feel that if they're a holiday goer or a tourist, I feel that they've planned their holiday and it's costly etc to get there," he said.

"They want to go and see a certain site or walk a certain trail, and they're just going to do it regardless of what conditions present.

"I think if you map crucial errors in heat stroke events, it tends to come down to the planning."

With hot outback temperatures predicted to continue, authorities will be praying their warnings are heeded, and another grim search avoided this summer.