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Most popular bushwalking areas in Australia are warm to very hot for some months of the year. In some areas, the summer months are too hot for bushwalking. Even in the cooler and wetter parts of southeast Australia, during the summer months successive days hot weather occur each summer.
In all areas, naturally occurring drinking water can be scarce or non-existent, depending on the season.
Trip planning for hot dry conditions
Trip planning must take into account the possibility of hot and dry conditions, including:
- The range of temperatures to be expected.
- Shorter days or rest days when temperatures are high.
- The availability and reliability of drinking water sources.
- The availability of water at each camp site.
- “Dry” camps are best avoided unless water is carried for only a short distance.
- The amount of water the group will need to carry each day.
- Ensuring group members have the fitness and are able to carry sufficient water.
- Planning water drops if necessary.
- Clothing suitable for hot and dry conditions.
- An awareness of heat illnesses.
- Food suitable for hot and dry conditions
- Total fire ban days.
Prior to departure:
- Confirm with land managers that water sources are available.
- Check the weather forecast. If extreme heat or very high fire danger is expected, cancel or modify the trip.
Heat illness
High temperatures or a shortage of drinking water, or both, can result in a heat illness. A sound knowledge of these illnesses, their causes and their treatment is a very important element in being well prepared for walks in hot dry conditions. The illnesses include:
- Heat cramps
- Exercise Associated Collapse (previously called heat exhaustion)
- Heat stroke: a very serious medical emergency, potentially fatal.
See Heat illnesses for more information.
A group member developing a heat illness on a bushwalk is very serious. When that occurs, the rest of the group should be monitored carefully, as other group members may be close to becoming distressed too.
A mild heat illness will prevent an individual from walking at the required pace, or walking at all. This can result in the group being unable to reach a planned fresh supply of drinking water. This puts the rest of the group at a much greater risk of also developing heat illnesses.
A larger group may be able to deal with the situation by splitting the group and having some members go ahead to fetch water. A small group or solo walker will not have this option.
Heat stroke is a very serious and potentially fatal condition. The patient needs to be cooled quickly. The best way to do this is with water, but if the only water available is the group’s limited supply of drinking water, the situation will be dire.
Emergency services should be contacted using the group’s emergency communications device.
Considerations for walking in hot weather
If a day is going to be hot:
- Consider making it a rest day or a short day.
- Make an early start, even before dawn.
- Ensure each group member is carrying sufficient water.
- Have an extended rest during the hottest part of the day.
- If possible, avoid steep climbs during the hottest part of the day.
- Rest in the shade.
- Monitor group members for any signs of distress.
- Everyone should wear a hat.
- Hot feet swell and are more likely to develop blisters – treat hot spots early.
- Navigate carefully, to ensure that no additional effort is needed due to a navigation error.
- Be alert for the possibility of thunderstorms later in the day.
Minimum water requirements
The quantities are a rough guide only. There can be considerable variation in daily water requirements, depending on factors such as weather conditions, the nature of the route, fitness of individuals and loads being carried.
- For cool conditions, the minimum daily water requirement is about 2.5 to 3 litres per person per day.
- For hot conditions or when undertaking strenuous activity, this can rise to at least 6 litres per day.
- For a “dry” overnight camp, an additional 3 to 4 litres per person is needed.
Heat related illnesses, including heat stroke, are serious conditions.
Clothing
Clothing should be lightweight, light coloured or white, and loose fitting. Covering the head and neck with a wide-brimmed hat, shirt collar and/or neck cloth are sensible, if not essential.
A lightweight fly net may be very useful in some areas. Daily use of insect repellents on a long trip is impractical and may cause skin irritation and reduce the ability to sweat.
See Clothing for more information.
Lost or broken down in arid country or hot weather
Becoming lost in hot weather with limited or no drinking water is a very dangerous situation. It is most unsafe to continue on hoping that the situation will resolve or to have group members wandering about looking for water.
- If the group is lost, stop.
- Stay in the shade.
- Keep up off hot ground.
- Keep the body covered, especially the neck and head.
- Minimise muscle action during intense heat.
- Wear sunglasses and a hat.
- Drink when thirsty, but avoid eating, as this uses up water for digestion.
- Keep the mouth shut and minimise talk.
- Consider available resources: water, food, clothing, shelter, first aid, emergency communications and signals. Ration available water.
- Do not walk unless absolutely necessary and then only in the cool of the early morning and late evening or night.
- Walk slowly and rest often. In critical situations save urine, not for drinking but for cooling the body.
- A smoky fire or a flashing mirror will assist in being located by a search party or an aircraft.
Note: This advice also applies if a vehicle has broken down in arid country in hot weather: remain in the vicinity of the vehicle.
If a group is lost, low on water, or has a member with a serious heat illness or injury, contact emergency services immediately. Make your location as visible as possible.
Dodgy approaches for obtaining water
Some wilderness survival literature describes various methods for finding water in arid country including: digging in the gravel of dry creek beds, seeking water in a gorge, following birds, sponging dew and condensation off the tent, fastening plastic bags over the leafy ends of branches to collect the resulting condensation, dripping water out of succulent leaves and roots of certain plants, or building a solar still.
It is NOT POSSIBLE to obtain sufficient water to survive using such methods, without significant local knowledge, much practice and a great deal of luck. They cannot be relied upon.