Urban Heat and Heat Waves

Heatwaves are perhaps our most under-rated natural hazard. In Australia during the 20th century, heatwaves caused more deaths than any other natural hazard.

What is a heatwave?

A heatwave is a prolonged period of 3 or more consecutive days of excessive heat. In Australia excessive heat can vary from 35°C to 42°C.

This unusual and uncomfortable hot weather can impact on human and animal health and cause disruption to community infrastructure such as power supply, public transport and services.  

Who is vulnerable to the affects of a heatwave?

Although everyone is vulnerable to the affects of a heatwave, those most at risk are:  

  • babies and children under four years
  • seniors and older people living alone
  • pregnant women, breast feeding mothers and infants
  • people taking medications that may interfere with the body’s ability to regulate temperature.

Anyone with:  

  • a chronic or mental illness
  • health conditions that may impair sweating
  • limited or poor mobility
  • excess body weight (overweight)

People who undertake vigorous exercise during a heatwave (including animals) are also susceptible to its effects.

How do I avoid heat stress for myself and my family?

  • Wear lightweight, light-coloured, loose, porous natural fibre clothes
  • Avoid strenuous activities
  • Drink two to three litres of water per day, even if not thirsty
  • Avoid alcoholic, caffeinated or carbonated (soft) drinks
  • Don't take salt tablets unless prescribed by a doctor
  • Avoid protein foods such as meat, dairy products which increase body heat and fluid loss
  • Keep your home cool with curtains, shutters, or awnings on the sunny sides and open windows at night
  • If you don't have air conditioning, use fans, damp clothing and have frequent cool showers
  • Spend as much time as possible in air conditioned buildings (e.g. shopping centres, art galleries, libraries, museums)
  • Avoid direct sunlight. Wear a hat and sunscreen as sunburn limits your ability to cope with heat
  • If you work outside, keep hat and clothing damp
  • Don't leave children or pets in parked vehicles
  • If you suffer chronic illness or feel ill, see your doctor
  • Keep animals in the shade with plenty of water

Related Information

Urban Heat

Research tells us that cities are hotter than their rural surroundings. In fact, cities can be between 20C to 120C warmer.

The reason behind this is that cities and built environments are largely made of surfaces that absorb heat, like roads, footpaths concrete walls and roofs. We know that vegetation, canopy cover and the presence of water are important components to cooling our City. As such, we are collaborating with a number of organisations and stakeholders to better understand urban heat and identify ways we can work together to mitigate and adapt to this challenge.

Monitoring heat

In partnership with Western Sydney University (WSU), we placed 110 temperature sensors across the Local Government Area (LGA) during the 2018/19 summer.

The sensors collected over 1.4 million temperature measurements at 10-minute intervals, and found:

  1. The 2018/19 summer broke LGA records
    • The LGA experienced three heatwaves. During one heatwave event, maximum daily air temperatures remained above 38°C for eight consecutive days (heatwaves are defined as events where maximum daily air temperature remains above 38°C for a minimum of three consecutive days)
    • January 2019 was the hottest month with an average daytime air temperature of 29.9°C and an average nighttime air temperature of 21.7°C.
  2. Not all suburbs in the LGA feel the heat equally
    • Absolute maximum temperatures ranged from 37.4°C to 45.4°C
    • Daytime air temperature regularly varied by around 6°C across the LGA
    • During days of extreme heat, air temperatures varied by more than 10°C across the LGA
    • During a cool change experienced on a day of extreme heat, a temperature variation of more than 17°C was recorded between Kooringa Reserve in St Andrews (measuring 43.3°C) and Hodgson Close in Wedderburn (measuring 26°C).
  3. The LGA is hot
    • There is a significant underreporting of temperature by official weather stations. Our closest Bureau of Meteorology weather station at the Australian Botanic Gardens, Mt Annan only recorded 23 days over 35°C compared to the sensors, which recorded 54 days over 35°C. Additionally, the weather station only recorded 1 day over 40°C, compared to the sensors, which recorded 22 days over 40°C.

Read the full report here: Benchmarking Heat Across Campbelltown(PDF, 6MB).

Urban Heat Island

We participated in a multi-agency working party, facilitated by the Cooperative Research Centre for Low Carbon Living (CRCLCL), which developed an urban heat island mitigation decision-support tool.

This is the first study of its kind that will also quantify the impacts of urban heat on energy consumption and human health

Cool seal project

Two main contributors to heating our urban areas are pavements and roads. Typically, these surfaces cover 25-50 per cent of the urban landscape, and are usually impermeable, hard and heavy. During summer, peak temperatures can reach well above 60°C, resulting in these surfaces requiring considerably more time to cool down.

Council has collaborated with Parramatta City and Blacktown Council and is utilising the research expertise of Western Sydney University, to pilot a product that has demonstrated reduced surface temperatures by up to 14°C on average.

The product is a bitumen based sealcoat, which has been applied to two existing car park surfaces - H.J Daley Library carpark and the Council staff carpark, south side.

Western Sydney University has also installed a number of air temperature sensors to monitor the cooling benefits.

Extreme Heat and Heat Waves

When energy demand increases during a heat wave, electrical infrastructure is more likely to overload and fail, causing air conditioners to stop working and outages to communication networks.

Extreme heat is our biggest risk in terms of shocks, it kills more Australians than any other natural disaster with heatwaves being more deadly than storms, fires and floods combined.

Heat-related mortality can be up to three times higher in Western Sydney than in Eastern parts of Sydney during heatwave periods. During a heat wave your body works extra hard to maintain a normal temperature, which can lead to death in vulnerable people.

Recognise the signs of heat-related illness

Heat Related Illnesses What are the signs?
Deterioration in existing medical conditions This is the most common health problem of heat stress.
Heat rash This is a skin irritation caused by excessive sweating. It looks like a red cluster of pimples or small blisters. In this instance, you would move the person to a cooler, less humid environment and keep the affected area dry. Try using unperfumed talcum powder to increase comfort. Avoid using any ointments or creams.
Heat cramps These include muscle pains or spasms, usually in the abdomen, arms or legs. They may occur after strenuous activity in a hot environment, usually when the body gets depleted of salt and water. Cramps may also be a symptom of heat exhaustion. In this case, you must immediately stop the activity that is being conducted and sit quietly in a cool place and increase fluid intake. Rest for a few hours before returning to an activity or seek medical help if there is no improvement.
Dizziness and fainting Heat related dizziness and fainting results from a reduced blood flow to the brain. Heat causes an increase in blood flow to the skin and pooling of blood in the legs, which can lead to a sudden drop in blood pressure. There can be a feeling of light-headedness before fainting occurs. Get the person to a cool area and lay them down. If fully conscious you can increase fluid intake.
Heat exhaustion This is a serious condition that can develop into heatstroke, occurring when excessive sweating in a hot environment reduces the blood volume. Warning signs may include paleness and sweating, rapid heart rate, muscle cramps, headaches, nausea and vomiting, dizziness or fainting. Get the person to a cool area and lay them down. Remove outer clothing and wet skin with cool water or wet cloths. Increase fluid intake if they are fully conscious and seek medical advice.
Heatstroke - this is a medical emergency and requires urgent attention Heatstroke occurs when the core body temperature rises above 40.5 °C and the body's internal systems start to shut down. The sufferer may stagger, appear confused, have a fit or collapse and become unconscious, there can be damage to the nervous system, liver, kidney, muscles and heart. Immediately call triple zero (000) for an ambulance. Get the person to a cool area and lay them down while you are waiting for emergency medical help. Remove outer clothing and wet skin with cool water and fan continuously. Do not give the person any fluids to drink. If they are unconscious position them on their side and clear their airways. If medical attention is delayed, seek further instructions from the ambulance or hospital emergency staff.

 

Staying safe during a heat wave

  • Never leave a child, adult or animal alone inside a vehicle on a warm day
  • Find cool zones to escape the heat, see our map to find your closest refuge
  • If you are outside, find shade and wear a hat wide enough to protect your face
  • Wear loose, lightweight, light-coloured clothing
  • Drink plenty of fluids to stay hydrated
  • Take it easy and avoid high intensity activities
  • Check in with family, friends and neighbours.

Keeping your home cool

  • Cover windows with blinds and curtains
  • Weather-strip doors and windows
  • Use window reflectors, such as aluminium foil-covered cardboard, to reflect heat back outside
  • Add insulation
  • Install double glazed windows.
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